Index: builtin.jam
===================================================================
--- builtin.jam	(revision 43575)
+++ builtin.jam	(working copy)
@@ -185,7 +185,7 @@
 
 # The addressing model to generate code for. Currently a limited set only
 # specifying the bit size of pointers.
-feature.feature address-model : 16 32 64 : propagated optional ;
+feature.feature address-model : 16 32 64 32_64 : propagated optional ;
 
 # Type of CPU architecture to compile for.
 feature.feature architecture :
Index: darwin.jam
===================================================================
--- darwin.jam	(revision 43575)
+++ darwin.jam	(working copy)
@@ -115,6 +115,10 @@
 {
     feature.set-default macosx-version : 10.4 ;
 }
+if 10.5 in [ feature.values macosx-version ]
+{
+    feature.set-default macosx-version : 10.5 ;
+}
 
 # Add the options for all the found SDKs.
 for local sdk in $(.macosx-sdk)
@@ -146,14 +150,18 @@
         : $(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 ;
 
 
 flags darwin.link OPTIONS <runtime-link>static