(Only the first 10 of 12 ports in this commit are shown above. )
With the release of GCC 8.5 the GCC 8 release series has reached
end of life.
This also means the end of weekly snapshots. Remove lang/gcc8-devel
which has been tracking those and redirect to lang/gcc8 and that
final release instead.
Update to the 20180308 snapshot of GCC 8.3.1.
No longer require a not too old version of GCC to build on powerpc64, but
rely on the system compiler (even if that means we need to be explicitly
conservative when it comes to optimizations). 
Sync pkg-descr with lang/gcc7-devel, in particular after r442530 there.
PR: 235975 
Submitted by: Piotr Kubaj <email@example.com> 
Welcome GCC 8! GCC 7 (provided via lang/gcc7-devel) has been branched
for the release and this first GCC 8 snapshot is still very close to that,
whereas the coming months are going to provide a rougher ride through
the development stages of GCC 8.