Created attachment 198215 [details]
-Wno-c++11-narrowing is unavailable in base GCC.
It's enough to add USE_CXXSTD=c++98, this makes this port build with both base GCC and LLVM.
Tested on powerpc64 and amd64.
Hardware sponsored by IntegriCloud.
Created attachment 198220 [details]
Small correction, additional fix is necessary.
A commit references this bug:
Date: Sun Oct 28 19:35:20 UTC 2018
New revision: 483328
Fix build on powerpc64.
Submitted by: Piotr Kubaj
Approved by: portmgr (tier-2 blanket)