[libc] fix preferred_type attribute detection (#95599)

SchrodingerZhu · web-flow · commit 2146d12eb940 · 2024-06-14T13:51:39.000-07:00
diff --git a/libc/src/__support/macros/attributes.h b/libc/src/__support/macros/attributes.h
@@ -42,7 +42,7 @@
 #define LIBC_CONSTINIT
 #endif
 
-#ifdef __clang__
+#if defined(__clang__) && __has_attribute(preferred_type)
 #define LIBC_PREFERED_TYPE(TYPE) [[clang::preferred_type(TYPE)]]
 #else
 #define LIBC_PREFERED_TYPE(TYPE)
