auto_popen
f = auto_popen("mount_nfs", "-o", options, "-R", retrycnt,
f = auto_popen("mount", "-t", fstype, "-o", options,
yyin = auto_popen(AUTO_INCLUDE_PATH, map, NULL);
yyin = auto_popen(path, key, NULL);
yyin = auto_popen(path, NULL);
yyin = auto_popen(AUTO_INCLUDE_PATH, n->n_key + 1, NULL);
yyin = auto_popen(path, key, NULL);
FILE *auto_popen(const char *, ...);