grep bug with large zero-filled file

[Ronnie Misra]

I've discovered a bug in grep on Mac OS X, which also reproduces with  
the stock FSF grep-2.5.4:

* create a large empty file. I did this with:
        dd if=/dev/zero of=/tmp/out bs=1024k count=800
* run
        grep foo /tmp/out

In my tests, grep's memory usage continues to grow until it eventually  
crashes.

Ronnie