[PATCH] gen_build_files.sh: Remove bashisms

[Peter Tyser]

> But, we could still have fun discussing how we go about making the scripts
> as portable as possible and avoid breaking peoples builds, I presume.
> And this is, IMO, the main point to this flamy exchange of ideas.
> 
> Take care Rob.  And try to focus on the matter at hand, which should not
> be "which shell is best", but how to make the scripts portable.

I 100% agree.  Participating in this discussion is like wrestling a
greased pig:)  I also echo your opinions about keeping the scripts
portable.

Best,
Peter