> I'm not sure if there's a particular reason to treat the BEL character
> specially here. The \a escape has been available forever. It's in K&R.
> I think it's clearer, cleaner, and more consistent to use that. 

But then you'll need to address the many other uses of \007 in the tree.

And for the reason why \a is not used, have a look at the comment in
bin/ksh/c_ksh.c: at some point, pcc did not support \a.