Uses Werror everywhere
/bin/bash ./libtool --tag=FC --mode=compile /var/tmp/notmpfs/portage/sys-devel/gcc-5.4.0-r3/work/build/./gcc/gfortran -B/var/tmp/notmpfs/portage/sys-devel/gcc-5.4.0-r3/work/build/./gcc/ -B/usr/x86_64-pc-linux-gnu/bin/ -B/usr/x86_64-pc-linux-gnu/lib/ -isystem /usr/x86_64-pc-linux-gnu/include -isystem /usr/x86_64-pc-linux-gnu/sys-include -I . -Wall -Werror -fimplicit-none -fno-repack-arrays -fno-underscoring -fallow-leading-underscore -O2 -pipe -march=native -mtune=native -Wno-error=implicit-function-declaration -D_REENTRANT -Wl,-flto -c -o dprod_r8.lo `test -f 'intrinsics/dprod_r8.f90' || echo '/var/tmp/notmpfs/portage/sys-devel/gcc-5.4.0-r3/work/gcc-5.4.0/l
Created attachment 472562 [details]
*** Bug 621178 has been marked as a duplicate of this bug. ***
That's one of the few packages where I'm not going to patch that out.
As per https://wiki.gentoo.org/wiki/Project:Toolchain/Support_policies building of two major versions older GCC is intended to be supported, even with -Werror used.
I'd reopen this bug for that, but... there is no error, it built fine and the log contains no errors. If it actually fails to build with 1 or 2 major versions newer GCC, then report that, not -Werror in case of GCC (-Werror is wrong in most other packages still and probably worth a bug report).