Update: use gnu99 default in gcc15

Author: vcaesar

hook.go

@@ -14,7 +14,7 @@ package hook
 #cgo darwin CFLAGS: -x objective-c -Wno-deprecated-declarations
 #cgo darwin LDFLAGS: -framework Cocoa
 
-#cgo linux CFLAGS:-I/usr/src -std=gnu17
+#cgo linux CFLAGS:-I/usr/src -std=gnu99
 #cgo linux LDFLAGS: -L/usr/src -lX11 -lXtst
 #cgo linux LDFLAGS: -lX11-xcb -lxcb -lxcb-xkb -lxkbcommon -lxkbcommon-x11
 //#cgo windows LDFLAGS: -lgdi32 -luser32