[patch/rfc;testsuite] Append patchlevel to compiler_info

[Andrew Cagney]

> This is good.  I think it needs a comment that gcc supports
> __GNUC_PATCHLEVEL__ starting with gcc 3.0, so that we know how long
> we need to keep the conditional logic.

True.

> Can you do a before-and-after test with gcc 2.95.3 and with some
> version of gcc 3.X ?

I've already done that.

> I expect that all the "gcc-2-*" and "gcc-*-*"
> will continue to work but that really needs testing.  They can be
> improved to "gcc-2-*-*" and "gcc-*-*-*" later.

I was thinking more of changing ``gcc-*-*'' to ``gcc-*''.

> Hmmm, come to think of it, I don't know if "gcc-*-*-*" will match
> "gcc-2-95-".  How about if you make the unknown case "gcc-X-Y-UNKNOWN"
> instead of "gcc-X-Y-".

It works as is, however I can append "-unknown" - I suspect that's 
better than the ucase "-UNKNOWN".

Andrew