Re: warn about conflicting skeleton-generated files

[Paolo Bonzini]

> 1. If the file name does not contain a `/', it's one of Bison's installed 
> skeleton files.
>
> 2. If the file name does contain a `/', it's an absolute or relative file 
> name.  If it's relative, it's relative to where the file name was 
> specified (current working directory for the command-line, and grammar 
> file directory for the grammar file).

No Unix utility behaves like this with respect to data files (even
though your comparison with how shells look in the PATH is right).
IMHO, the right way to do it would be: If the file name does not contain
a `/', and is not found in the current directory, it's one of Bison's
installed files.  This is the same as include paths in C, and it fits
better than the comparison with shells looking up the commands.  This is
partially backwards-incompatible, in case someone has a lalr1.cc file in
their current directory, but people should switch to %language anyway.

I think that this behavior is easy to implement on top of your patch.

Also, you're not modifying -S if I understand correctly.  The
parse-gram.y code should have been in skeleton_arg instead.

Paolo