exec_common
err = exec_common((char *)arg1, (const char **)arg2,
error = exec_common(path, argp, envp, vp, EBA_NONE);
error = exec_common(fname, argp, envp, NULL, EBA_NONE);
error = exec_common((const char *)exec_fnamep,
extern int exec_common(const char *, const char **, const char **, vnode_t *,