Add a sym link to help llvm-gcc find dsymutil.  <rdar://problem/10720980>

llvm-svn: 150350
diff --git a/llvm-gcc-4.2/build_gcc b/llvm-gcc-4.2/build_gcc
index ac5611c..9dbebcf 100755
--- a/llvm-gcc-4.2/build_gcc
+++ b/llvm-gcc-4.2/build_gcc
@@ -525,6 +525,7 @@
   # LLVM LOCAL begin fix broken link
   ln -s ../../../../../bin/as .$DL/as
   ln -s ../../../../../bin/ld .$DL/ld
+  ln -s ../../../../../bin/dsymutil .$DL/dsymutil
   # LLVM LOCAL end fix broken link
 done