Index: darwin.jam
===================================================================
--- darwin.jam	(revision 86767)
+++ darwin.jam	(working copy)
@@ -64,10 +64,13 @@
      <architecture>x86/<address-model>32
      <architecture>x86/<address-model>64
      <architecture>x86/<instruction-set>
+     <architecture>x86/<address-model>32/<instruction-set>
      <architecture>power/<address-model>32
      <architecture>power/<address-model>64
      <architecture>power/<instruction-set>  ;
 
+toolset.flags darwin OPTIONS <architecture>x86/<address-model>32/<instruction-set> : -march=prescott ;
+
 # Options:
 #
 #   <root>PATH
@@ -194,6 +197,9 @@
     
     # - Initialize the SDKs available in the root for this tool.
     local sdks = [ init-available-sdk-versions $(condition) : $(root) ] ;
+    sdks += [ init-available-sdk-versions $(condition) :
+        /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer
+        ] ;
     
     #~ ECHO --- ;
     #~ ECHO --- bin :: $(bin) ;