Index: build/toolset.jam
===================================================================
--- build/toolset.jam	(revision 57269)
+++ build/toolset.jam	(working copy)
@@ -449,7 +449,7 @@
 }
 
 
-rule inherit-rules ( toolset : base )
+rule inherit-rules ( toolset : base : localize ? )
 {
     # It appears that "action" creates a local rule.
     local base-generators = [ generators.generators-for-toolset $(base) ] ;
@@ -459,8 +459,8 @@
         rules += [ MATCH "[^.]*\.(.*)" : [ $(g).rule-name ] ] ;
     }
     rules = [ sequence.unique $(rules) ] ;
-    IMPORT $(base) : $(rules) : $(toolset) : $(rules) ;
-    IMPORT $(base) : $(rules) : : $(toolset).$(rules) ;
+    IMPORT $(base) : $(rules) : $(toolset) : $(rules) : $(localize) ;
+    IMPORT $(toolset) : $(rules) : : $(toolset).$(rules) ;
 }
 
 
Index: tools/darwin.jam
===================================================================
--- tools/darwin.jam	(revision 57269)
+++ tools/darwin.jam	(working copy)
@@ -16,6 +16,9 @@
 import common ;
 import generators ;
 import path : basename ;
+import version ;
+import property-set ;
+import regex ;
 
 ## Use a framework.
 feature framework : : free ;
@@ -60,7 +63,7 @@
 
 type.set-generated-target-suffix PCH : <toolset>darwin : gch ;
 
-toolset.inherit-rules darwin : gcc ;
+toolset.inherit-rules darwin : gcc : localize ;
 toolset.inherit-flags darwin : gcc     
   :  <runtime-link>static
      <architecture>arm/<address-model>32
@@ -121,6 +124,8 @@
         version ?= $(real-version) ;
     }
     
+    .real-version.$(version) = $(real-version) ;
+    
     # - Define the condition for this toolset instance.
     local condition =
         [ common.check-init-parameters darwin $(requirement) : version $(version) ] ;
@@ -265,10 +270,102 @@
 generators.register-c-compiler darwin.compile.m : OBJECTIVE_C : OBJ : <toolset>darwin ;
 generators.register-c-compiler darwin.compile.mm : OBJECTIVE_CPP : OBJ : <toolset>darwin ;
 
-rule compile.m
+rule setup-address-model ( targets * : sources * : properties * )
 {
+    local ps = [ property-set.create $(properties) ] ;
+    local arch = [ $(ps).get <architecture> ] ;
+    local address-model = [ $(ps).get <address-model> ] ;
+    local osx-version = [ $(ps).get <macosx-version> ] ;
+    local gcc-version = [ $(ps).get <toolset-darwin:version> ] ;
+    gcc-version = $(.real-version.$(gcc-version)) ;
+    local options ;
+    
+    local support-ppc64 = 1 ;
+    if $(osx-version) && ! [ version.less [ regex.split $(osx-version) . ] : 10 6 ]
+    {
+        # When targeting 10.6:
+        # - gcc 4.2 will give a compiler errir if ppc64 compilation is requested
+        # - gcc 4.0 will compile fine, somehow, but then fail at link time
+        support-ppc64 = ;
+    }
+           
+    switch $(arch)
+    {
+        case combined : 
+        {
+            if $(address-model) = 32_64 {
+                if $(support-ppc64) {
+                    options = -arch i386 -arch ppc -arch x86_64 -arch ppc64 ;                    
+                } else {
+                    # Build 3-way binary
+                    options = -arch i386 -arch ppc -arch x86_64 ;
+                }                                
+            } else if $(address-model) = 64 {
+                if $(support-ppc64) {
+                    options = -arch x86_64 -arch ppc64 ;
+                } else {
+                    errors.user-error "64-bit PPC compilation is not supported when targeting OSX 10.6 or later" ;
+                }                
+            } else {
+                options = -arch i386 -arch ppc ;
+            }
+        }
+        
+        case x86 : 
+        {
+            if $(address-model) = 32_64 {
+                options = -arch i386 -arch x86_64 ;
+            } else if $(address-model) = 64 {
+                options = -arch x86_64 ;
+            } else {
+                options = -arch i386 ;
+            }
+        }        
+        
+        case power :
+        {
+            if ! $(support-ppc64) 
+              && (  $(address-model) = 32_64 || $(address-model) = 64 )
+            {
+                errors.user-error "64-bit PPC compilation is not supported when targeting OSX 10.6 or later" ;
+            }
+            
+            if $(address-model) = 32_64 {
+                options = -arch ppc -arch ppc64 ;
+            } else if $(address-model) = 64 {
+                options = -arch ppc64 ;
+            } else {
+                options = -arch ppc ;
+            }
+        }
+        
+        case arm :
+        {
+            options = -arch armv6 ;
+        }        
+    }
+    
+    if $(options)
+    {
+        OPTIONS on $(targets) += $(options) ;
+    }            
+}
+
+rule setup-threading ( targets * : sources * : properties * )
+{
+    gcc.setup-threading $(targets) : $(sources) : $(properties) ;
+}
+
+rule setup-fpic ( targets * : sources * : properties * )
+{
+    gcc.setup-fpic $(targets) : $(sources) : $(properties) ;
+}
+
+rule compile.m ( targets * : sources * : properties * )
+{
     LANG on $(<) = "-x objective-c" ;
     gcc.setup-fpic $(targets) : $(sources) : $(properties) ;
+    setup-arch-addr-flags $(targets) : $(sources) : $(properties) ;
 }
 
 actions compile.m
@@ -280,6 +377,7 @@
 {
     LANG on $(<) = "-x objective-c++" ;
     gcc.setup-fpic $(targets) : $(sources) : $(properties) ;
+    setup-arch-addr-flags $(targets) : $(sources) : $(properties) ;
 }
 
 actions compile.mm
@@ -287,37 +385,6 @@
     "$(CONFIG_COMMAND)" $(LANG) $(OPTIONS) $(USER_OPTIONS) -D$(DEFINES) -I"$(INCLUDES)" -c -o "$(<)" "$(>)"
 }
 
-# Add option selection for combined and specific architecture combinations.
-
-local rule arch-addr-flags ( toolset variable
-    : architecture : address-model + : values + : default ? )
-{
-    if $(default)
-    {
-        flags $(toolset) $(variable)
-            <architecture>$(architecture)/<address-model>
-            : $(values) ;
-    }
-    flags $(toolset) $(variable)
-        <architecture>/<address-model>$(address-model)
-        <architecture>$(architecture)/<address-model>$(address-model)
-        : $(values) ;
-}
-
-arch-addr-flags darwin OPTIONS : combined : 32 : -arch i386 -arch ppc : default ;
-arch-addr-flags darwin OPTIONS : combined : 64 : -arch x86_64 -arch ppc64 ;
-arch-addr-flags darwin OPTIONS : combined : 32_64 : -arch i386 -arch ppc -arch x86_64 -arch ppc64 ;
-
-arch-addr-flags darwin OPTIONS : x86 : 32 : -arch i386 : default ;
-arch-addr-flags darwin OPTIONS : x86 : 64 : -arch x86_64 ;
-arch-addr-flags darwin OPTIONS : x86 : 32_64 : -arch i386 -arch x86_64 ;
-
-arch-addr-flags darwin OPTIONS : power : 32 : -arch ppc : default ;
-arch-addr-flags darwin OPTIONS : power : 64 : -arch ppc64 ;
-arch-addr-flags darwin OPTIONS : power : 32_64 : -arch ppc -arch ppc64 ;
-
-arch-addr-flags darwin OPTIONS : arm : 32 : -arch armv6 : default ;
-
 # Set the max header padding to allow renaming of libs for installation.
 flags darwin.link.dll OPTIONS : -headerpad_max_install_names ;