Enable __arm__ on apple

llvm-svn: 152735
diff --git a/libcxxabi/include/cxxabi.h b/libcxxabi/include/cxxabi.h
index b0994d1..f769b86 100644
--- a/libcxxabi/include/cxxabi.h
+++ b/libcxxabi/include/cxxabi.h
@@ -64,7 +64,7 @@
 extern LIBCXXABI_NORETURN void __cxa_deleted_virtual(void);
 
 // 3.3.2 One-time Construction API
-#ifdef LIBCXXABI_ARMEABI
+#if __arm__
 extern int  __cxa_guard_acquire(uint32_t*);
 extern void __cxa_guard_release(uint32_t*);
 extern void __cxa_guard_abort(uint32_t*);