[libgfortran, build] Remove AC_TRY_* macros from libgfortran configury

[Ralf Wildenhues]

* FX wrote on Tue, Mar 15, 2011 at 10:33:01AM CET:
> The attached patch replaces the deprecated AC_TRY_{COMPILE,LINK,RUN}
> macros in libgfortran configury with their AC_*_IFELSE equivalents.
> Now (4.7 just branched) seems a good time, and I think I didn't screw
> it too much because the regenerated configure file only has whitespace
> changes. Still, I'd like to have the opinion of a build maintainer or
> autoconf guru.
> 
> Bootstrapped and regtested on x86_64-darwin.
> 
> OK to commit to trunk?

Yes, thanks.

Out of curiosity, did you update these manually, or did you run
autoupdate on the files?

Thanks,
Ralf