Conditionally wrap the changes from r134781.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@134783 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/locale b/include/locale
index 4a65eb6..778d6c6 100644
--- a/include/locale
+++ b/include/locale
@@ -192,8 +192,10 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
+#ifndef _LIBCPP_STABLE_APPLE_ABI
 // Get the C locale object
 locale_t __cloc();
+#endif
 
 // OSX has nice foo_l() functions that let you turn off use of the global
 // locale.  Linux, not so much.  The following functions avoid the locale when