[libgfortran,patch] New autoconf test

[François-Xavier Coudert]

>>   b) would it work in a cross-compiler setup?
>
> When building non-native binaries, e.g. build=i686-pc-linux-gnu and
> host=target=sparc-sun-solaris2.9, this will probably fail since one can not
> execute sparc binaries on i686?!

I thought that, for a (build = B) != (host = target = T), we need two
different gfortran compilers: the final one, with configuration
described above, and one with (build = host = B) and target = T; then,
libgfortran is configured and built with the second one. At least,
that's what I think.

FX