[Bug libfortran/68347] Multiple build errors in libgfortran

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68347

--- Comment #8 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
> ... results in valid output.

So Mikael probably got the point: don't buil in the source directory. Instead
of

> cd gcc-5.2.0
> mkdir build && cd build
> ../configure --disable-multilib
> make

do

cd gcc-5.2.0
mkdir ../build && cd ../build
../gcc-5.2.0/configure --disable-multilib
make

(or similar!-).