/*[XSI]*/ #if 202405L <= _POSIX_C_SOURCE #define _XOPEN_SOURCE 800 #elif 200809L <= _POSIX_C_SOURCE #define _XOPEN_SOURCE 700 #endif #include #ifdef getutxline #undef getutxline #endif struct utmpx *(*foo)(const struct utmpx *) = getutxline; int main(void) { return 0; }