macro: clean up usage of gcc attributes

Always use our own macros, and name all our own macros the same style.

src/core/execute.c

@@ -511,7 +511,7 @@ fail:
         return r;
 }
 
-_printf_attr_(1, 2) static int write_confirm_message(const char *format, ...) {
+_printf_(1, 2) static int write_confirm_message(const char *format, ...) {
         int fd;
         va_list ap;