Merge remote branch 'upstream/master'

Conflicts:
	Jamroot
	bjam
	decoder/Jamfile
	decoder/cdec.cc
	dpmert/Jamfile
	jam-files/sanity.jam
	klm/lm/Jamfile
	klm/util/Jamfile
	mira/Jamfile

1 files changed, 0 insertions, 1317 deletions

diff --git a/jam-files/boost-build/build/virtual-target.jam b/jam-files/boost-build/build/virtual-target.jam
deleted file mode 100644
index 2e8446bc..00000000
--- a/jam-files/boost-build/build/virtual-target.jam
+++ /dev/null
@@ -1,1317 +0,0 @@
-# Copyright 2003 Dave Abrahams
-# Copyright 2005, 2006 Rene Rivera
-# Copyright 2002, 2003, 2004, 2005, 2006 Vladimir Prus
-# Distributed under the Boost Software License, Version 1.0.
-# (See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
-
-# Implements virtual targets, which correspond to actual files created during a
-# build, but are not yet targets in Jam sense. They are needed, for example,
-# when searching for possible transformation sequences, when it is not yet known
-# whether a particular target should be created at all.
-
-import "class" : new ;
-import errors ;
-import path ;
-import sequence ;
-import set ;
-import type ;
-import utility ;
-
-
-#                       +--------------------------+
-#                       | virtual-target           |
-#                       +==========================+
-#                       | actualize                |
-#                       +--------------------------+
-#                       | actualize-action() = 0   |
-#                       | actualize-location() = 0 |
-#                       +----------------+---------+
-#                                        |
-#                                        ^
-#                                       / \
-#                                      +-+-+
-#                                        |
-#    +---------------------+     +-------+--------------+
-#    | action              |     | abstract-file-target |
-#    +=====================|   * +======================+
-#    | action-name         |  +--+ action               |
-#    | properties          |  |  +----------------------+
-#    +---------------------+--+  | actualize-action()   |
-#    | actualize()         |0..1 +-----------+----------+
-#    | path()              |                 |
-#    | adjust-properties() | sources         |
-#    | actualize-sources() | targets         |
-#    +------+--------------+                 ^
-#           |                               / \
-#           ^                              +-+-+
-#          / \                               |
-#         +-+-+                +-------------+-------------+
-#           |                  |                           |
-#           |           +------+---------------+  +--------+-------------+
-#           |           | file-target          |  | searched-lib-target  |
-#           |           +======================+  +======================+
-#           |           | actualize-location() |  | actualize-location() |
-#           |           +----------------------+  +----------------------+
-#           |
-#         +-+------------------------------+
-#         |                                |
-#    +----+----------------+     +---------+-----------+
-#    | compile-action      |     | link-action         |
-#    +=====================+     +=====================+
-#    | adjust-properties() |     | adjust-properties() |
-#    +---------------------+     | actualize-sources() |
-#                                +---------------------+
-#
-# The 'compile-action' and 'link-action' classes are not defined here but in
-# builtin.jam modules. They are shown in the diagram to give the big picture.
-
-
-# Models a potential target. It can be converted into a Jam target and used in
-# building, if needed. However, it can be also dropped, which allows us to
-# search for different transformations and select only one.
-#
-class virtual-target
-{
-    import scanner ;
-    import sequence ;
-    import utility ;
-    import virtual-target ;
-
-    rule __init__ (
-          name     # Target/project name.
-        : project  # Project to which this target belongs.
-    )
-    {
-        self.name = $(name) ;
-        self.project = $(project) ;
-        self.dependencies = ;
-    }
-
-    # Name of this target.
-    #
-    rule name ( )
-    {
-        return $(self.name) ;
-    }
-
-    # Project of this target.
-    #
-    rule project ( )
-    {
-        return $(self.project) ;
-    }
-
-    # Adds additional 'virtual-target' instances this one depends on.
-    #
-    rule depends ( d + )
-    {
-        self.dependencies = [ sequence.merge $(self.dependencies) :
-            [ sequence.insertion-sort $(d) ] ] ;
-    }
-
-    rule dependencies ( )
-    {
-        return $(self.dependencies) ;
-    }
-    
-    rule always ( )
-    {
-        .always = 1 ;
-    }
-    
-    # Generates all the actual targets and sets up build actions for this
-    # target.
-    #
-    # If 'scanner' is specified, creates an additional target with the same
-    # location as the actual target, which will depend on the actual target and
-    # be associated with a 'scanner'. That additional target is returned. See
-    # the docs (#dependency_scanning) for rationale. Target must correspond to a
-    # file if 'scanner' is specified.
-    #
-    # If scanner is not specified then the actual target is returned.
-    #
-    rule actualize ( scanner ? )
-    {
-        local actual-name = [ actualize-no-scanner ] ;
-        
-        if $(.always)
-        {
-            ALWAYS $(actual-name) ;
-        }
-        
-        if ! $(scanner)
-        {
-            return $(actual-name) ;
-        }
-        else
-        {
-            # Add the scanner instance to the grist for name.
-            local g = [ sequence.join
-                [ utility.ungrist $(actual-name:G) ] $(scanner) : - ] ;
-            local name = $(actual-name:G=$(g)) ;
-
-            if ! $(self.made.$(name))
-            {
-                self.made.$(name) = true ;
-
-                DEPENDS $(name) : $(actual-name) ;
-
-                actualize-location $(name) ;
-
-                scanner.install $(scanner) : $(name) $(__name__) ;
-            }
-            return $(name) ;
-        }
-    }
-
-# private: (overridables)
-
-    # Sets up build actions for 'target'. Should call appropriate rules and set
-    # target variables.
-    #
-    rule actualize-action ( target )
-    {
-        errors.error "method should be defined in derived classes" ;
-    }
-
-    # Sets up variables on 'target' which specify its location.
-    #
-    rule actualize-location ( target )
-    {
-        errors.error "method should be defined in derived classes" ;
-    }
-
-    # If the target is a generated one, returns the path where it will be
-    # generated. Otherwise, returns an empty list.
-    #
-    rule path ( )
-    {
-        errors.error "method should be defined in derived classes" ;
-    }
-
-    # Returns the actual target name to be used in case when no scanner is
-    # involved.
-    #
-    rule actual-name ( )
-    {
-        errors.error "method should be defined in derived classes" ;
-    }
-
-# implementation
-    rule actualize-no-scanner ( )
-    {
-        # In fact, we just need to merge virtual-target with
-        # abstract-file-target as the latter is the only class derived from the
-        # former. But that has been left for later.
-	
-        errors.error "method should be defined in derived classes" ;
-    }
-}
-
-
-# Target corresponding to a file. The exact mapping for file is not yet
-# specified in this class. (TODO: Actually, the class name could be better...)
-#
-# May be a source file (when no action is specified) or a derived file
-# (otherwise).
-#
-# The target's grist is a concatenation of its project's location, action
-# properties (for derived targets) and, optionally, value identifying the main
-# target.
-#
-class abstract-file-target : virtual-target
-{
-    import project ;
-    import regex ;
-    import sequence ;
-    import path ;
-    import type ;
-    import property-set ;
-    import indirect ;
-
-    rule __init__ (
-         name     # Target's name.
-         exact ?  # If non-empty, the name is exactly the name created file
-                  # should have. Otherwise, the '__init__' method will add a
-                  # suffix obtained from 'type' by calling
-                  # 'type.generated-target-suffix'.
-        : type ?  # Target's type.
-        : project
-        : action ?
-    )
-    {
-        virtual-target.__init__ $(name) : $(project) ;
-
-        self.type = $(type) ;
-        self.action = $(action) ;
-        if $(action)
-        {
-            $(action).add-targets $(__name__) ;
-
-            if $(self.type) && ! $(exact)
-            {
-                _adjust-name $(name) ;
-            }
-        }
-    }
-
-    rule type ( )
-    {
-        return $(self.type) ;
-    }
-
-    # Sets the path. When generating target name, it will override any path
-    # computation from properties.
-    #
-    rule set-path ( path )
-    {
-        self.path = [ path.native $(path) ] ;
-    }
-
-    # Returns the currently set action.
-    #
-    rule action ( )
-    {
-        return $(self.action) ;
-    }
-
-    # Sets/gets the 'root' flag. Target is root if it directly corresponds to
-    # some variant of a main target.
-    #
-    rule root ( set ? )
-    {
-        if $(set)
-        {
-            self.root = true ;
-        }
-        return $(self.root) ;
-    }
-
-    # Gets or sets the subvariant which created this target. Subvariant is set
-    # when target is brought into existance and is never changed after that. In
-    # particular, if a target is shared by a subvariant, only the first is
-    # stored.
-    #
-    rule creating-subvariant ( s ?  # If specified, specifies the value to set,
-                                    # which should be a 'subvariant' class
-                                    # instance.
-                             )
-    {
-        if $(s) && ! $(self.creating-subvariant)
-        {
-            self.creating-subvariant = $(s) ;
-        }
-        return $(self.creating-subvariant) ;
-    }
-
-    rule actualize-action ( target )
-    {
-        if $(self.action)
-        {
-            $(self.action).actualize ;
-        }
-    }
-
-    # Return a human-readable representation of this target. If this target has
-    # an action, that is:
-    #
-    #    { <action-name>-<self.name>.<self.type> <action-sources>... }
-    #
-    # otherwise, it is:
-    #
-    #    { <self.name>.<self.type> }
-    #
-    rule str ( )
-    {
-        local action = [ action ] ;
-        local name-dot-type = [ sequence.join $(self.name) "." $(self.type) ] ;
-
-        if $(action)
-        {
-            local sources     = [ $(action).sources     ] ;
-            local action-name = [ $(action).action-name ] ;
-
-            local ss ;
-            for local s in $(sources)
-            {
-                ss += [ $(s).str ] ;
-            }
-
-            return "{" $(action-name)-$(name-dot-type) $(ss) "}" ;
-        }
-        else
-        {
-            return "{" $(name-dot-type) "}" ;
-        }
-    }
-
-    rule less ( a )
-    {
-        if [ str ] < [ $(a).str ]
-        {
-            return true ;
-        }
-    }
-
-    rule equal ( a )
-    {
-        if [ str ] = [ $(a).str ]
-        {
-            return true ;
-        }
-    }
-
-# private:
-    rule actual-name ( )
-    {
-        if ! $(self.actual-name)
-        {
-            local grist = [ grist ] ;
-            local basename = [ path.native $(self.name) ] ;
-            self.actual-name = <$(grist)>$(basename) ;
-        }
-        return $(self.actual-name) ;
-    }
-
-    # Helper to 'actual-name', above. Computes a unique prefix used to
-    # distinguish this target from other targets with the same name creating
-    # different files.
-    #
-    rule grist ( )
-    {
-        # Depending on target, there may be different approaches to generating
-        # unique prefixes. We generate prefixes in the form:
-        # <one letter approach code> <the actual prefix>
-        local path = [ path ] ;
-        if $(path)
-        {
-            # The target will be generated to a known path. Just use the path
-            # for identification, since path is as unique as it can get.
-            return p$(path) ;
-        }
-        else
-        {
-            # File is either source, which will be searched for, or is not a
-            # file at all. Use the location of project for distinguishing.
-            local project-location = [ $(self.project).get location ] ;
-            local location-grist = [ sequence.join [ regex.split
-                $(project-location) "/" ] : "!" ] ;
-
-            if $(self.action)
-            {
-                local ps = [ $(self.action).properties ] ;
-                local property-grist = [ $(ps).as-path ] ;
-                # 'property-grist' can be empty when 'ps' is an empty property
-                # set.
-                if $(property-grist)
-                {
-                    location-grist = $(location-grist)/$(property-grist) ;
-                }
-            }
-
-            return l$(location-grist) ;
-        }
-    }
-
-    # Given the target name specified in constructor, returns the name which
-    # should be really used, by looking at the <tag> properties. Tag properties
-    # need to be specified as <tag>@rule-name. This makes Boost Build call the
-    # specified rule with the target name, type and properties to get the new
-    # name. If no <tag> property is specified or the rule specified by <tag>
-    # returns nothing, returns the result of calling
-    # virtual-target.add-prefix-and-suffix.
-    #
-    rule _adjust-name ( specified-name )
-    {
-        local ps ;
-        if $(self.action)
-        {
-            ps = [ $(self.action).properties ] ;
-        }
-        else
-        {
-            ps = [ property-set.empty ] ;
-        }
-
-        # We add ourselves to the properties so that any tag rule can get more
-        # direct information about the target than just that available through
-        # the properties. This is useful in implementing name changes based on
-        # the sources of the target. For example to make unique names of object
-        # files based on the source file.  --grafik
-        ps = [ property-set.create [ $(ps).raw ] <target>$(__name__) ] ;
-
-        local tag = [ $(ps).get <tag> ] ;
-
-        if $(tag)
-        {
-            local rule-name = [ MATCH ^@(.*) : $(tag) ] ;
-            if $(rule-name)
-            {
-                if $(tag[2])
-                {
-                    errors.error "<tag>@rulename is present but is not the only"
-                        "<tag> feature" ;
-                }
-
-                self.name = [ indirect.call $(rule-name) $(specified-name)
-                    : $(self.type) : $(ps) ] ;
-            }
-            else
-            {
-                errors.error
-                    "The value of the <tag> feature must be '@rule-name'" ;
-            }
-        }
-
-        # If there is no tag or the tag rule returned nothing.
-        if ! $(tag) || ! $(self.name)
-        {
-            self.name = [ virtual-target.add-prefix-and-suffix $(specified-name)
-                : $(self.type) : $(ps) ] ;
-        }
-    }
-
-    rule actualize-no-scanner ( )
-    {
-        local name = [ actual-name ] ;
-
-        # Do anything only on the first invocation.
-        if ! $(self.made.$(name))
-        {
-            self.made.$(name) = true ;
-
-            if $(self.action)
-            {
-                # For non-derived target, we do not care if there are several
-                # virtual targets that refer to the same name. One case when
-                # this is unavoidable is when the file name is main.cpp and two
-                # targets have types CPP (for compiling) and MOCCABLE_CPP (for
-                # conversion to H via Qt tools).
-                virtual-target.register-actual-name $(name) : $(__name__) ;
-            }
-
-            for local i in $(self.dependencies)
-            {
-                DEPENDS $(name) : [ $(i).actualize ] ;
-            }
-
-            actualize-location $(name) ;
-            actualize-action $(name) ;
-        }
-        return $(name) ;
-    }
-}
-
-
-# Appends the suffix appropriate to 'type/property-set' combination to the
-# specified name and returns the result.
-#
-rule add-prefix-and-suffix ( specified-name : type ? : property-set )
-{
-    local suffix = [ type.generated-target-suffix $(type) : $(property-set) ] ;
-
-    # Handle suffixes for which no leading dot is desired. Those are specified
-    # by enclosing them in <...>.  Needed by python so it can create "_d.so"
-    # extensions, for example.
-    if $(suffix:G)
-    {
-        suffix = [ utility.ungrist $(suffix) ] ;
-    }
-    else
-    {
-        suffix = .$(suffix) ;
-    }
-
-    local prefix = [ type.generated-target-prefix $(type) : $(property-set) ] ;
-
-    if  [ MATCH ^($(prefix)) : $(specified-name) ]
-    {
-        prefix = ;
-    }
-    return $(prefix:E="")$(specified-name)$(suffix:E="") ;
-}
-
-
-# File targets with explicitly known location.
-#
-# The file path is determined as
-#    * Value passed to the 'set-path' method, if any.
-#    * For derived files, project's build dir, joined with components that
-#      describe action properties. If free properties are not equal to the
-#      project's reference properties an element with the name of the main
-#      target is added.
-#    * For source files, project's source dir.
-#
-# The file suffix is determined as:
-#     * The value passed to the 'suffix' method, if any.
-#     * The suffix corresponding to the target's type.
-#
-class file-target : abstract-file-target
-{
-    import "class" : new ;
-    import common ;
-    import errors ;
-
-    rule __init__ (
-        name exact ?
-        : type ?  # Optional type for this target.
-        : project
-        : action ?
-        : path ?
-    )
-    {
-        abstract-file-target.__init__ $(name) $(exact) : $(type) : $(project) :
-            $(action) ;
-
-        self.path = $(path) ;
-    }
-
-    rule clone-with-different-type ( new-type )
-    {
-        return [ new file-target $(self.name) exact : $(new-type) :
-            $(self.project) : $(self.action) : $(self.path) ] ;
-    }
-
-    rule actualize-location ( target )
-    {
-        if $(self.action)
-        {
-            # This is a derived file.
-            local path = [ path ] ;
-            LOCATE on $(target) = $(path) ;
-
-            # Make sure the path exists.
-            DEPENDS $(target) : $(path) ;
-            common.MkDir $(path) ;
-
-            # It is possible that the target name includes a directory too, for
-            # example when installing headers. Create that directory.
-            if $(target:D)
-            {
-                local d = $(target:D) ;
-                d = $(d:R=$(path)) ;
-                DEPENDS $(target) : $(d) ;
-                common.MkDir $(d) ;
-            }
-
-            # For a real file target, we create a fake target depending on the
-            # real target. This allows us to run
-            #
-            #    bjam hello.o
-            #
-            # without trying to guess the name of the real target. Note that the
-            # target has no directory name and uses a special <e> grist.
-            #
-            # First, that means that "bjam hello.o" will build all known hello.o
-            # targets. Second, the <e> grist makes sure this target will not be
-            # confused with other targets, for example, if we have subdir 'test'
-            # with target 'test' in it that includes a 'test.o' file, then the
-            # target for directory will be just 'test' the target for test.o
-            # will be <ptest/bin/gcc/debug>test.o and the target we create below
-            # will be <e>test.o
-            DEPENDS $(target:G=e) : $(target) ;
-            # Allow bjam <path-to-file>/<file> to work. This will not catch all
-            # possible ways to refer to the path (relative/absolute, extra ".",
-            # various "..", but should help in obvious cases.
-            DEPENDS $(target:G=e:R=$(path)) : $(target) ;
-        }
-        else
-        {
-            SEARCH on $(target) = [ path.native $(self.path) ] ;
-        }
-    }
-
-    # Returns the directory for this target.
-    #
-    rule path ( )
-    {
-        if ! $(self.path)
-        {
-            if $(self.action)
-            {
-                local p = [ $(self.action).properties ] ;
-                local path,relative-to-build-dir = [ $(p).target-path ] ;
-                local path = $(path,relative-to-build-dir[1]) ;
-                local relative-to-build-dir = $(path,relative-to-build-dir[2]) ;
-
-                if $(relative-to-build-dir)
-                {
-                    path = [ path.join [ $(self.project).build-dir ] $(path) ] ;
-                }
-
-                self.path = [ path.native $(path) ] ;
-            }
-        }
-        return $(self.path) ;
-     }
-}
-
-
-class notfile-target : abstract-file-target
-{
-    rule __init__ ( name : project : action ? )
-    {
-        abstract-file-target.__init__ $(name) : : $(project) : $(action) ;
-    }
-
-    # Returns nothing to indicate that the target's path is not known.
-    #
-    rule path ( )
-    {
-        return ;
-    }
-
-    rule actualize-location ( target )
-    {
-        NOTFILE $(target) ;
-        ALWAYS $(target) ;
-        # TEMPORARY $(target) ;
-        NOUPDATE $(target) ;
-    }
-}
-
-
-# Class representing an action. Both 'targets' and 'sources' should list
-# instances of 'virtual-target'. Action name should name a rule with this
-# prototype:
-#     rule action-name ( targets + : sources * : properties * )
-# Targets and sources are passed as actual Jam targets. The rule may not
-# establish additional dependency relationships.
-#
-class action
-{
-    import "class" ;
-    import errors ;
-    import type ;
-    import toolset ;
-    import property-set ;
-    import indirect ;
-    import path ;
-    import set : difference ;
-
-    rule __init__ ( sources * : action-name + : property-set ? )
-    {
-        self.sources = $(sources) ;
-
-        self.action-name = [ indirect.make-qualified $(action-name) ] ;
-
-        if ! $(property-set)
-        {
-            property-set = [ property-set.empty ] ;
-        }
-
-        if ! [ class.is-instance $(property-set) ]
-        {
-            errors.error "Property set instance required" ;
-        }
-
-        self.properties = $(property-set) ;
-    }
-
-    rule add-targets ( targets * )
-    {
-        self.targets += $(targets) ;
-    }
-
-    rule replace-targets ( old-targets * : new-targets * )
-    {
-        self.targets = [ set.difference $(self.targets) : $(old-targets) ] ;
-        self.targets += $(new-targets) ;
-    }
-
-    rule targets ( )
-    {
-        return $(self.targets) ;
-    }
-
-    rule sources ( )
-    {
-        return $(self.sources) ;
-    }
-
-    rule action-name ( )
-    {
-        return $(self.action-name) ;
-    }
-
-    rule properties ( )
-    {
-        return $(self.properties) ;
-    }
-
-    # Generates actual build instructions.
-    #
-    rule actualize ( )
-    {
-        if ! $(self.actualized)
-        {
-            self.actualized = true ;
-
-            local ps = [ properties ] ;
-            local properties = [ adjust-properties $(ps) ] ;
-
-            local actual-targets ;
-            for local i in [ targets ]
-            {
-                actual-targets += [ $(i).actualize ] ;
-            }
-
-            actualize-sources [ sources ] : $(properties) ;
-
-            DEPENDS $(actual-targets) : $(self.actual-sources)
-                $(self.dependency-only-sources) ;
-            
-            # This works around a bug with -j and actions that
-            # produce multiple target, where:
-            # - dependency on the first output is found, and
-            #   the action is started
-            # - dependency on the second output is found, and
-            #   bjam noticed that command is already running
-            # - instead of waiting for the command, dependents
-            #   of the second targets are immediately updated.
-            if $(actual-targets[2])
-            {                
-                INCLUDES $(actual-targets) : $(actual-targets) ;
-            }
-            
-            # Action name can include additional argument to rule, which should
-            # not be passed to 'set-target-variables'
-            toolset.set-target-variables
-                [ indirect.get-rule $(self.action-name[1]) ] $(actual-targets)
-                : $(properties) ;
-
-            # Reflect ourselves in a variable for the target. This allows
-            # looking up additional info for the action given the raw target.
-            # For example to debug or output action information from action
-            # rules.
-            .action on $(actual-targets) = $(__name__) ;
-
-            indirect.call $(self.action-name) $(actual-targets)
-                : $(self.actual-sources) : [ $(properties).raw ] ;
-
-            # Since we set up the creating action here, we set up the action for
-            # cleaning up as well.
-            common.Clean clean-all : $(actual-targets) ;
-        }
-    }
-
-    # Helper for 'actualize-sources'. For each passed source, actualizes it with
-    # the appropriate scanner. Returns the actualized virtual targets.
-    #
-    rule actualize-source-type ( sources * : property-set )
-    {
-        local result = ;
-        for local i in $(sources)
-        {
-            local scanner ;
-            if [ $(i).type ]
-            {
-                scanner = [ type.get-scanner [ $(i).type ] : $(property-set) ] ;
-            }
-            result += [ $(i).actualize $(scanner) ] ;
-        }
-        return $(result) ;
-    }
-
-    # Creates actual Jam targets for sources. Initializes the following member
-    # variables:
-    #   'self.actual-sources'          -- sources passed to the updating action.
-    #   'self.dependency-only-sources' -- sources marked as dependencies, but
-    #                                     are not used otherwise.
-    #
-    # New values will be *appended* to the variables. They may be non-empty if
-    # caller wants it.
-    #
-    rule actualize-sources ( sources * : property-set )
-    {
-        local dependencies = [ $(self.properties).get <dependency> ] ;
-
-        self.dependency-only-sources +=
-            [ actualize-source-type $(dependencies) : $(property-set) ] ;
-        self.actual-sources +=
-            [ actualize-source-type $(sources) : $(property-set) ] ;
-
-        # This is used to help bjam find dependencies in generated headers and
-        # other main targets, e.g. in:
-        #
-        #   make a.h : ....... ;
-        #   exe hello : hello.cpp : <implicit-dependency>a.h ;
-        #
-        # For bjam to find the dependency the generated target must be
-        # actualized (i.e. have its Jam target constructed). In the above case,
-        # if we are building just hello ("bjam hello"), 'a.h' will not be
-        # actualized unless we do it here.
-        local implicit = [ $(self.properties).get <implicit-dependency> ] ;
-        for local i in $(implicit)
-        {
-            $(i:G=).actualize ;
-        }
-    }
-
-    # Determines real properties when trying to build with 'properties'. This is
-    # the last chance to fix properties, for example to adjust includes to get
-    # generated headers correctly. Default implementation simply returns its
-    # argument.
-    #
-    rule adjust-properties ( property-set )
-    {
-        return $(property-set) ;
-    }
-}
-
-
-# Action class which does nothing --- it produces the targets with specific
-# properties out of nowhere. It is needed to distinguish virtual targets with
-# different properties that are known to exist and have no actions which create
-# them.
-#
-class null-action : action
-{
-    rule __init__ ( property-set ? )
-    {
-        action.__init__ : .no-action : $(property-set) ;
-    }
-
-    rule actualize ( )
-    {
-        if ! $(self.actualized)
-        {
-            self.actualized = true ;
-            for local i in [ targets ]
-            {
-                $(i).actualize ;
-            }
-        }
-    }
-}
-
-
-# Class which acts exactly like 'action', except that its sources are not
-# scanned for dependencies.
-#
-class non-scanning-action : action
-{
-    rule __init__ ( sources * : action-name + : property-set ? )
-    {
-        action.__init__ $(sources) : $(action-name) : $(property-set) ;
-    }
-
-    rule actualize-source-type ( sources * : property-set )
-    {
-        local result ;
-        for local i in $(sources)
-        {
-            result += [ $(i).actualize ] ;
-        }
-        return $(result) ;
-    }
-}
-
-
-# Creates a virtual target with an appropriate name and type from 'file'. If a
-# target with that name in that project already exists, returns that already
-# created target.
-#
-# FIXME: a more correct way would be to compute the path to the file, based on
-# name and source location for the project, and use that path to determine if
-# the target has already been created. This logic should be shared with how we
-# usually find targets identified by a specific target id. It should also be
-# updated to work correctly when the file is specified using both relative and
-# absolute paths.
-#
-# TODO: passing a project with all virtual targets is starting to be annoying.
-#
-rule from-file ( file : file-loc : project )
-{
-    import type ;  # Had to do this here to break a circular dependency.
-
-    # Check whether we already created a target corresponding to this file.
-    local path = [ path.root [ path.root $(file) $(file-loc) ] [ path.pwd ] ] ;
-
-    if $(.files.$(path))
-    {
-        return $(.files.$(path)) ;
-    }
-    else
-    {
-        local name = [ path.make $(file) ] ;
-        local type = [ type.type $(file) ] ;
-        local result ;
-
-        result = [ new file-target $(file) : $(type) : $(project) : :
-            $(file-loc) ] ;
-
-        .files.$(path) = $(result) ;
-        return $(result) ;
-    }
-}
-
-
-# Registers a new virtual target. Checks if there is already a registered target
-# with the same name, type, project and subvariant properties as well as the
-# same sources and equal action. If such target is found it is returned and a
-# new 'target' is not registered. Otherwise, 'target' is registered and
-# returned.
-#
-rule register ( target )
-{
-    local signature = [ sequence.join
-        [ $(target).path ] [ $(target).name ] : - ] ;
-
-    local result ;
-    for local t in $(.cache.$(signature))
-    {
-        local a1 = [ $(t).action ] ;
-        local a2 = [ $(target).action ] ;
-
-        if ! $(result)
-        {
-            if ! $(a1) && ! $(a2)
-            {
-                result = $(t) ;
-            }
-            else
-            {
-                if $(a1) && $(a2) &&
-                    ( [ $(a1).action-name ] = [ $(a2).action-name ] ) &&
-                    ( [ $(a1).sources     ] = [ $(a2).sources     ] )
-                {
-                    local ps1 = [ $(a1).properties ] ;
-                    local ps2 = [ $(a2).properties ] ;
-                    local p1 = [ $(ps1).base ] [ $(ps1).free ] [ set.difference
-                        [ $(ps1).dependency ] : [ $(ps1).incidental ] ] ;
-                    local p2 = [ $(ps2).base ] [ $(ps2).free ] [ set.difference
-                        [ $(ps2).dependency ] : [ $(ps2).incidental ] ] ;
-                    if $(p1) = $(p2)
-                    {
-                        result = $(t) ;
-                    }
-                }
-            }
-        }
-    }
-
-    if ! $(result)
-    {
-        .cache.$(signature) += $(target) ;
-        result = $(target) ;
-    }
-
-    .recent-targets += $(result) ;
-    .all-targets += $(result) ;
-
-    return $(result) ;
-}
-
-
-# Each target returned by 'register' is added to the .recent-targets list,
-# returned by this function. This allows us to find all virtual targets created
-# when building a specific main target, even those constructed only as
-# intermediate targets.
-#
-rule recent-targets ( )
-{
-    return $(.recent-targets) ;
-}
-
-
-rule clear-recent-targets ( )
-{
-    .recent-targets = ;
-}
-
-
-# Returns all virtual targets ever created.
-#
-rule all-targets ( )
-{
-    return $(.all-targets) ;
-}
-
-
-# Returns all targets from 'targets' with types equal to 'type' or derived from
-# it.
-#
-rule select-by-type ( type : targets * )
-{
-    local result ;
-    for local t in $(targets)
-    {
-        if [ type.is-subtype [ $(t).type ] $(type) ]
-        {
-            result += $(t) ;
-        }
-    }
-    return $(result) ;
-}
-
-
-rule register-actual-name ( actual-name : virtual-target )
-{
-    if $(.actual.$(actual-name))
-    {
-        local cs1 = [ $(.actual.$(actual-name)).creating-subvariant ] ;
-        local cs2 = [ $(virtual-target).creating-subvariant ] ;
-        local cmt1 = [ $(cs1).main-target ] ;
-        local cmt2 = [ $(cs2).main-target ] ;
-
-        local action1 = [ $(.actual.$(actual-name)).action ] ;
-        local action2 = [ $(virtual-target).action ] ;
-        local properties-added ;
-        local properties-removed ;
-        if $(action1) && $(action2)
-        {
-            local p1 = [ $(action1).properties ] ;
-            p1 = [ $(p1).raw ] ;
-            local p2 = [ $(action2).properties ] ;
-            p2 = [ $(p2).raw ] ;
-            properties-removed = [ set.difference $(p1) : $(p2) ] ;
-            properties-removed ?= "none" ;
-            properties-added = [ set.difference $(p2) : $(p1) ] ;
-            properties-added ?= "none" ;
-        }
-        errors.error "Duplicate name of actual target:" $(actual-name)
-            : "previous virtual target" [ $(.actual.$(actual-name)).str ]
-            : "created from"            [ $(cmt1).full-name ]
-            : "another virtual target"  [ $(virtual-target).str ]
-            : "created from"            [ $(cmt2).full-name ]
-            : "added properties:"       $(properties-added)
-            : "removed properties:"     $(properties-removed) ;
-    }
-    else
-    {
-        .actual.$(actual-name) = $(virtual-target) ;
-    }
-}
-
-
-# Traverses the dependency graph of 'target' and return all targets that will be
-# created before this one is created. If the root of some dependency graph is
-# found during traversal, it is either included or not, depending on the
-# 'include-roots' value. In either case traversal stops at root targets, i.e.
-# root target sources are not traversed.
-#
-rule traverse ( target : include-roots ? : include-sources ? )
-{
-    local result ;
-    if [ $(target).action ]
-    {
-        local action = [ $(target).action ] ;
-        # This includes the 'target' as well.
-        result += [ $(action).targets ] ;
-
-        for local t in [ $(action).sources ]
-        {
-            if ! [ $(t).root ]
-            {
-                result += [ traverse $(t) : $(include-roots) : $(include-sources) ] ;
-            }
-            else if $(include-roots)
-            {
-                result += $(t) ;
-            }
-        }
-    }
-    else if $(include-sources)
-    {
-        result = $(target) ;
-    }
-    return $(result) ;
-}
-
-
-# Takes an 'action' instance and creates a new instance of it and all targets
-# produced by the action. The rule-name and properties are set to
-# 'new-rule-name' and 'new-properties', if those are specified. Returns the
-# cloned action.
-#
-rule clone-action ( action : new-project : new-action-name ? : new-properties ? )
-{
-    if ! $(new-action-name)
-    {
-        new-action-name = [ $(action).action-name ] ;
-    }
-    if ! $(new-properties)
-    {
-        new-properties = [ $(action).properties ] ;
-    }
-
-    local action-class = [ modules.peek $(action) : __class__ ] ;
-    local cloned-action = [ class.new $(action-class)
-        [ $(action).sources ] : $(new-action-name) : $(new-properties) ] ;
-
-    local cloned-targets ;
-    for local target in [ $(action).targets ]
-    {
-        local n = [ $(target).name ] ;
-        # Do not modify produced target names.
-        local cloned-target = [ class.new file-target $(n) exact :
-            [ $(target).type ] : $(new-project) : $(cloned-action) ] ;
-        local d = [ $(target).dependencies ] ;
-        if $(d)
-        {
-            $(cloned-target).depends $(d) ;
-        }
-        $(cloned-target).root [ $(target).root ] ;
-        $(cloned-target).creating-subvariant [ $(target).creating-subvariant ] ;
-
-        cloned-targets += $(cloned-target) ;
-    }
-
-    return $(cloned-action) ;
-}
-
-
-class subvariant
-{
-    import sequence ;
-    import type ;
-
-    rule __init__ ( main-target       # The instance of main-target class.
-        : property-set                # Properties requested for this target.
-        : sources *
-        : build-properties            # Actually used properties.
-        : sources-usage-requirements  # Properties propagated from sources.
-        : created-targets * )         # Top-level created targets.
-    {
-        self.main-target = $(main-target) ;
-        self.properties = $(property-set) ;
-        self.sources = $(sources) ;
-        self.build-properties = $(build-properties) ;
-        self.sources-usage-requirements = $(sources-usage-requirements) ;
-        self.created-targets = $(created-targets) ;
-
-        # Pre-compose a list of other dependency graphs this one depends on.
-        local deps = [ $(build-properties).get <implicit-dependency> ] ;
-        for local d in $(deps)
-        {
-            self.other-dg += [ $(d:G=).creating-subvariant ] ;
-        }
-
-        self.other-dg = [ sequence.unique $(self.other-dg) ] ;
-    }
-
-    rule main-target ( )
-    {
-        return $(self.main-target) ;
-    }
-
-    rule created-targets ( )
-    {
-        return $(self.created-targets) ;
-    }
-
-    rule requested-properties ( )
-    {
-        return $(self.properties) ;
-    }
-
-    rule build-properties ( )
-    {
-        return $(self.build-properties) ;
-    }
-
-    rule sources-usage-requirements ( )
-    {
-        return $(self.sources-usage-requirements) ;
-    }
-
-    rule set-usage-requirements ( usage-requirements )
-    {
-        self.usage-requirements = $(usage-requirements) ;
-    }
-
-    rule usage-requirements ( )
-    {
-        return $(self.usage-requirements) ;
-    }
-
-    # Returns all targets referenced by this subvariant, either directly or
-    # indirectly, and either as sources, or as dependency properties. Targets
-    # referred to using the dependency property are returned as properties, not
-    # targets.
-    #
-    rule all-referenced-targets ( theset )
-    {
-        # Find directly referenced targets.
-        local deps = [ $(self.build-properties).dependency ] ;
-        local all-targets = $(self.sources) $(deps) ;
-
-        # Find other subvariants.
-        local r ;
-        for local t in $(all-targets)
-        {
-            if ! [ $(theset).contains $(t) ]
-            {
-                $(theset).add $(t) ;
-                r += [ $(t:G=).creating-subvariant ] ;
-            }            
-        }
-        r = [ sequence.unique $(r) ] ;
-        for local s in $(r)
-        {
-            if $(s) != $(__name__)
-            {
-                $(s).all-referenced-targets $(theset) ;
-            }
-        }
-    }
-
-    # Returns the properties specifying implicit include paths to generated
-    # headers. This traverses all targets in this subvariant and subvariants
-    # referred by <implcit-dependecy> properties. For all targets of type
-    # 'target-type' (or for all targets, if 'target-type' is not specified), the
-    # result will contain <$(feature)>path-to-that-target.
-    #
-    rule implicit-includes ( feature : target-type ? )
-    {
-        local key = ii$(feature)-$(target-type:E="") ;
-        if ! $($(key))-is-not-empty
-        {
-            local target-paths = [ all-target-directories $(target-type) ] ;
-            target-paths = [ sequence.unique $(target-paths) ] ;
-            local result = $(target-paths:G=$(feature)) ;
-            if ! $(result)
-            {
-                result = "" ;
-            }
-            $(key) = $(result) ;
-        }
-        if $($(key)) = ""
-        {
-            return ;
-        }
-        else
-        {
-            return $($(key)) ;
-        }
-    }
-
-    rule all-target-directories ( target-type ? )
-    {
-        if ! $(self.target-directories)
-        {
-            compute-target-directories $(target-type) ;
-        }
-        return $(self.target-directories) ;
-    }
-
-    rule compute-target-directories ( target-type ? )
-    {
-        local result ;
-        for local t in $(self.created-targets)
-        {
-            # Skip targets of the wrong type.
-            if ! $(target-type) ||
-                [ type.is-derived [ $(t).type ] $(target-type) ]
-            {
-                result = [ sequence.merge $(result) : [ $(t).path ] ] ;
-            }
-        }
-        for local d in $(self.other-dg)
-        {
-            result += [ $(d).all-target-directories $(target-type) ] ;
-        }
-        self.target-directories = $(result) ;
-    }
-}