`jflex/bin/jflex` cannot resolves jar path.

# Cause
```bash
$ echo $LANG
ja_JP.UTF-8
$ type /bin/sh
/bin/sh は /bin/sh です
```
Finally, `$PRG` equals `です`.

# Solution
Force `LANG=C` 
```
$ LANG=C type /bin/sh
/bin/sh is /bin/sh
```
or use dirname, pwd to resolve path.