fix darwin8 bootstrap issue

       * compare-debug (Darwin): Remove '-x' flag from ld-based object
       stripping.  Add a comment as to why we do it this way.

From-SVN: r161686

contrib/ChangeLog

+2010-07-02  Iain Sandoe  <iains@gcc.gnu.org>
+
+       * compare-debug (Darwin): Remove '-x' flag from ld-based object
+       stripping.  Add a comment as to why we do it this way.
+
 2010-06-20  Alexandre Oliva  <aoliva@redhat.com>
 
 	* compare-debug: Drop LTO sections.

contrib/compare-debug

@@ -59,8 +59,10 @@ trap 'rm -f "$1.$suf1" "$2.$suf2"' 0 1 2 15
 
 case `uname -s` in
 Darwin)
-  ld -S -x -r -no_uuid "$1" -o "$1.$suf1"
-  ld -S -x -r -no_uuid "$2" -o "$2.$suf2"
+  # The strip command on darwin does not remove all debug info.
+  # Fortunately, we can use ld to do it instead.
+  ld -S -r -no_uuid "$1" -o "$1.$suf1"
+  ld -S -r -no_uuid "$2" -o "$2.$suf2"
   ;;
 *)
   cp "$1" "$1.$suf1"