getmntoptstr
const char *getmntoptstr(mntoptparse_t, const char *);
const char *val = getmntoptstr(mp, opt);
args.gid = getgrp(getmntoptstr(mp, "group"));
dbname = xstrcpy(getmntoptstr(mp, "dbname"));
dbuser = xstrcpy(getmntoptstr(mp, "dbuser"));