use pthread_getugid_np instead of gete{u,g}id on OSX. fixes #84
@ -34,8 +34,7 @@ namespace mergerfs
SetResetGuard(const uid_t _newuid,
const gid_t _newgid)
{
olduid = ::geteuid();
oldgid = ::getegid();
pthread_getugid_np(&olduid,&oldgid);
newuid = _newuid;
newgid = _newgid;