bug#37864: bug: env exec bomb (no hash bang arg)

[Michael Coleman]

One of my users unwittingly stumbled upon the most delightful 'env' bug.  It 
seems to be present in a couple of pretty recent distributions.

Try this:

----------------------------
#!/usr/bin/env
whatever
----------------------------

This results in an endless 'execve' recursion (if that's the word), pegging the 
CPU.

The preferred behavior would be something like a diagnostic, followed by 
immediate exit with an error result.

Regards,
Mike