process.c:2103
static VALUE
p_gid_exchangeable()
{
#if defined(HAVE_SETRESGID) &&  !defined(__CHECKER__)
    return Qtrue;
#elif defined(HAVE_SETREGID) && !defined(OBSOLETE_SETREGID)
    return Qtrue;
#else
    return Qfalse;
#endif
}
