Index: tools/build/jam_src/jam.h
===================================================================
RCS file: /cvsroot/boost/boost/tools/build/jam_src/jam.h,v
retrieving revision 1.20
diff -u -F^f -r1.20 jam.h
--- tools/build/jam_src/jam.h	16 Oct 2005 15:34:27 -0000	1.20
+++ tools/build/jam_src/jam.h	19 Dec 2005 16:39:16 -0000
@@ -451,26 +451,16 @@
 # if defined( _i386_ ) || \
      defined( __i386__ ) || \
      defined( _M_IX86 )
-# if !defined( OS_FREEBSD ) && \
-     !defined( OS_DRAGONFLYBSD ) && \
-     !defined( OS_OS2 ) && \
-     !defined( OS_AS400 )
 # define OSPLAT "OSPLAT=X86"
-# endif
 # endif 
 
 # ifdef __sparc__
-# if !defined( OS_SUNOS ) && \
-     !defined( OS_SOLARIS )
 # define OSPLAT "OSPLAT=SPARC"
 # endif
-# endif
 
 # ifdef __mips__
-# if !defined( OS_SGI )
 # define OSPLAT "OSPLAT=MIPS"
 # endif
-# endif
 
 # ifdef __arm__
 # define OSPLAT "OSPLAT=ARM"
@@ -480,6 +470,10 @@
 # define OSPLAT "OSPLAT=IA64"
 # endif
 
+# if defined(__amd64__) || defined(__x86_64__)
+# define OSPLAT "OSPLAT=X64"
+# endif
+
 # ifdef __s390__
 # define OSPLAT "OSPLAT=390"
 # endif