RFC: C/C++ preprocessor macro support for GDB

[Andrew Cagney]

> The following patch adds support for C/C++ preprocessor macros to GDB.
> It's tentative:
> 
> - There are no ChangeLog entries.
> - It's not broken up into relatively independent changes.
> - There's no documentation.
> - There are no tests.
> - There are some unimplemented features.
> 
> I'll put it in proper form and re-post it soon, but I'm putting it out
> now in hopes that folks will try it out and send me bug reports and
> suggestions.
> 
> The patch reads Dwarf 2 macro information, which GCC doesn't currently
> generate.  (In fact, I don't know if any compiler generates it at the
> moment.)  I've tested it against some hand-written ".debug_macinfo"
> sections, which I'll post in the next message.  So it's not actually
> useful yet.

Hmm, nice!

Andrew