[libcc1] Improve detection of triplet on compiler names

[Pedro Alves]

On 08/23/2017 05:17 AM, Sergio Durigan Junior wrote:
> The GCC patch improves the libcc1::compiler_triplet_regexp::find and
> libcp1::compiler_triplet_regexp::find methods by first trying to match
> the triplet in the compiler name and correctly discarding the triplet
> part of the regexp if the matching succeeds.  I've had to do a few
> modifications on the way the regexp's are built, but I'll explain them
> in the patch itself.
> 
> The GDB patch is very simple: it adds the trailing "-" in the triplet
> regexp.  Therefore, we will have a regexp that truly matches the full
> triplet (e.g., "^(x86_64|i.86)(-[^-]*)?-linux(-gnu)?-") instead of one
> that leaves the trailing "-" match to libcc1.
> 
> I've tested this patch both on my Fedora and my Debian machines, and
> both now work as expected, independently of the presence of the triplet
> string in the compiler name.  I am sorry about the cross-post, but these
> patches are really dependent on one another.

Is there a backward/forward compatibility impact?
Does new GDB work with old GCC?
Does old GDB work with new GCC?

Thanks,
Pedro Alves