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