Fix <rdar://problem/10136825>

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@141132 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/buildit b/lib/buildit
index 13d6f8e..0b191f3 100755
--- a/lib/buildit
+++ b/lib/buildit
@@ -26,7 +26,7 @@
 then
 	if [ -z $IPHONEOS_DEPLOYMENT_TARGET ]
 	then
-		MACOSX_DEPLOYMENT_TARGET=10.6
+		MACOSX_DEPLOYMENT_TARGET=10.7
 	fi
 fi
 
@@ -75,7 +75,8 @@
 			-lSystem  \
 			-Wl,-unexported_symbols_list,libc++unexp.exp  \
 			${RE_EXPORT_LINE}  \
-			-Wl,-force_symbols_not_weak_list,notweak.exp "
+			-Wl,-force_symbols_not_weak_list,notweak.exp \
+			-Wl,-force_symbols_weak_list,weak.exp"
 	fi
     ;;
   *-*-mingw*)