Define two pseudo targets for the target and build platform.

* The main build rules now cause their targets to depend on the
  platform such that global per-platform intializations can be
  set up by making the platform pseudo target depend on the
  target returned by the initialization rule.

build/jam/BuildSetup

@@ -861,6 +861,15 @@ PLATFORM = $(TARGET_PLATFORM) ;
 SUPPORTED_PLATFORMS = haiku ;
 
 
+# Define two pseudo targets for the target and buildhost platform. The main
+# build rules (Cc, C++, As, ...) depend on these pseude targets such that global
+# initializations that are required before anything is built for a specific
+# platform can be forced by depending the pseudo target for the platform on the
+# initializations.
+NotFile $(TARGET_PLATFORM) ;
+NotFile host ;
+
+
 # Instructs the Library rule to not make its object files temporary.
 # This is needed as some objects are used in a static library and for an
 # executable.

build/jam/MainBuildRules

@@ -168,7 +168,7 @@ rule StaticLibraryFromObjects
 
 rule AssembleNasm
 {
-	Depends $(<) : $(>) ;
+	Depends $(<) : $(>) [ on $(<) return $(PLATFORM) ] ;
 }
 
 actions AssembleNasm
@@ -343,7 +343,7 @@ rule CreateAsmStructOffsetsHeader header : source
 
 	# locate object, search for source, and set on target variables
 
-	Depends $(header) : $(source) ;
+	Depends $(header) : $(source) $(PLATFORM) ;
 	SEARCH on $(source) += $(SEARCH_SOURCE) ;
 	MakeLocateArch $(header) ;
 	LocalClean clean : $(header) ;

build/jam/OverriddenJamRules

@@ -210,7 +210,7 @@ rule As
 			= $(TARGET_SYSTEM_INCLUDES_OPTION_$(TARGET_PACKAGING_ARCH)) ;
 	}
 
-	Depends $(<) : $(>) ;
+	Depends $(<) : $(>) [ on $(1) return $(PLATFORM) ] ;
 	ASFLAGS on $(<) += $(flags) $(SUBDIRASFLAGS) ;
 	ASHDRS on $(<) = [ on $(<) FIncludes $(HDRS) : $(localIncludesOption) ]
 		$(includesSeparator)
@@ -227,7 +227,7 @@ actions As
 
 rule Lex
 {
-	Depends $(1) : $(2) ;
+	Depends $(1) : $(2) [ on $(1) return $(PLATFORM) ] ;
 	MakeLocateArch $(1) ;
 	LocalClean clean : $(1) ;
 }
@@ -245,7 +245,8 @@ rule Yacc
 
 	MakeLocateArch $(source) $(header) ;
 
-	Depends $(source) $(header) : $(yaccSource) ;
+	Depends $(source) $(header)
+		: $(yaccSource) [ on $(source) return $(PLATFORM) ] ;
 	Yacc1 $(source) $(header) : $(yaccSource) ;
 	LocalClean clean : $(source) $(header) ;
 
@@ -263,7 +264,7 @@ actions Yacc1
 
 rule Cc
 {
-	Depends $(<) : $(>) ;
+	Depends $(<) : $(>) [ on $(1) return $(PLATFORM) ] ;
 
 	on $(1) {
 		local flags ;
@@ -341,7 +342,7 @@ actions Cc
 
 rule C++
 {
-	Depends $(<) : $(>) ;
+	Depends $(<) : $(>) [ on $(1) return $(PLATFORM) ] ;
 
 	on $(1) {
 		local flags ;

src/tools/gensyscalls/Jamfile

@@ -35,7 +35,7 @@ rule PreprocessSyscalls preprocessedHeader : header : architecture
 {
 	# PreprocessSyscalls <preprocessedHeader> : <header> : <architecture> ;
 
-	Depends $(preprocessedHeader) : $(header) ;
+	Depends $(preprocessedHeader) : $(header) $(PLATFORM) ;
 
 	local headers = [ on $(preprocessedHeader)
 		return $(SEARCH_SOURCE) $(SUBDIRHDRS) $(HDRS) ] ;