Remove  -Wglobal-constructors from flags.  This was an accidental addition.

llvm-svn: 141551
diff --git a/libcxx/lib/buildit b/libcxx/lib/buildit
index d78bd3d..b307806 100755
--- a/libcxx/lib/buildit
+++ b/libcxx/lib/buildit
@@ -35,7 +35,7 @@
   RC_ProjectSourceVersion=1
 fi
 
-EXTRA_FLAGS="-std=c++0x -Wglobal-constructors"
+EXTRA_FLAGS="-std=c++0x"
 
 case $TRIPLE in
   *-apple-*)