8288101: False build warning-as-error with GCC 9 after JDK-8214976

Reviewed-by: mdoerr, zgu, kbarrett

src/hotspot/share/utilities/compilerWarnings_gcc.hpp

@@ -69,10 +69,13 @@
 
 #endif // clang/gcc version check
 
-#if (__GNUC__ >= 9) || (defined(__clang_major__) && (__clang_major__ >= 14))
+#if (__GNUC__ >= 10) || (defined(__clang_major__) && (__clang_major__ >= 14))
 
 // Use "warning" attribute to detect uses of "forbidden" functions.
 //
+// Note: The warning attribute is available since GCC 9, but disabling pragmas
+// does not work reliably in ALLOW_C_FUNCTION. GCC 10+ and up work fine.
+//
 // Note: _FORTIFY_SOURCE transforms calls to certain functions into calls to
 // associated "checking" functions, and that transformation seems to occur
 // *before* the attribute check.  We use fortification in fastdebug builds,
@@ -89,6 +92,6 @@
   __VA_ARGS__                                           \
   PRAGMA_DIAG_POP
 
-#endif // gcc9+ or clang14+
+#endif // gcc10+ or clang14+
 
 #endif // SHARE_UTILITIES_COMPILERWARNINGS_GCC_HPP