gcc-plugins: Remove TODO_verify_il for GCC >= 16

GCC now runs TODO_verify_il automatically[1], so it is no longer exposed to
plugins. Only use the flag on GCC < 16.

Link: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=9739ae9384dd7cd3bb1c7683d6b80b7a9116eaf8 [1]
Suggested-by: Christopher Fore <csfore@posteo.net>
Link: https://lore.kernel.org/r/20250920234519.work.915-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>

Author: kees

scripts/gcc-plugins/gcc-common.h

@@ -173,10 +173,17 @@ static inline opt_pass *get_pass_for_id(int id)
 	return g->get_passes()->get_pass_for_id(id);
 }
 
+#if BUILDING_GCC_VERSION < 16000
 #define TODO_verify_ssa TODO_verify_il
 #define TODO_verify_flow TODO_verify_il
 #define TODO_verify_stmts TODO_verify_il
 #define TODO_verify_rtl_sharing TODO_verify_il
+#else
+#define TODO_verify_ssa 0
+#define TODO_verify_flow 0
+#define TODO_verify_stmts 0
+#define TODO_verify_rtl_sharing 0
+#endif
 
 #define INSN_DELETED_P(insn) (insn)->deleted()