diff --git a/data/skeletons/glr.cc b/data/skeletons/glr.cc
index 343b52ef..4dd82970 100644
--- a/data/skeletons/glr.cc
+++ b/data/skeletons/glr.cc
@@ -267,7 +267,8 @@ b4_percent_code_get([[requires]])[
 
 // On MacOS, PTRDIFF_MAX is defined as long long, which Clang's
 // -pedantic reports as being a C++11 extension.
-#if defined __APPLE__ && YY_CPLUSPLUS < 201103L && 4 <= __clang_major__
+#if defined __APPLE__ && YY_CPLUSPLUS < 201103L \
+    && defined __clang__ && 4 <= __clang_major__
 # pragma clang diagnostic ignored "-Wc++11-long-long"
 #endif