Created attachment 197756 [details] patch USES=compiler:c++11-lang is necessary to build this port, otherwise CMake throws error. Tested on powercp64 and amd64. Hardware sponsored by IntegriCloud.
Tested it, and looks good to me. Note: Lately I haven't been able to use FreeBSD as much as I used to or would want to. If you feel like adopting the port, feel free to do so.
(In reply to Oliver Heesakkers from comment #1) I don't use this port either :) I'm just bulk-building all ports for powerpc64 and fixing what I can.
A commit references this bug: Author: linimon Date: Sun Oct 28 11:21:17 UTC 2018 New revision: 483277 URL: https://svnweb.freebsd.org/changeset/ports/483277 Log: Fix build with GCC-based architectures. PR: 231919 Submitted by: Piotr Kubaj Approved by: maintainer Changes: head/astro/gpsbabel/Makefile