I'm working on switching to LLVM's lld linker as the FreeBSD system linker (/usr/bin/ld), and the port in this PR is reported as a new failure in the exp-run, PR 214864.
An excerpt from the build log:
checking OS and machine type...
libunwind is missing.
Error: libunwind-devel is required.
===> Script "configure" failed unexpectedly.
The configure failure may be due to shared object protected visibility symbol preemption issues; setting LLD_UNSAFE=yes may be a suitable workaround (to use ld.bfd).
FreeBSD 11 and later have lld available as /usr/bin/ld.lld, so one simple option for testing is to just symlink /usr/bin/ld to ld.lld (and restore it to ld.bfd).
A port Makefile knob, LLD_UNSAFE=yes, exists to indicate that a port does not work with lld, and requires either /usr/bin/ld.bfd or binutils from ports. This should work for the common case of ports written in C using GNU autoconf; it may have no effect on other ports.
A commit references this bug:
Date: Wed May 30 12:34:16 UTC 2018
New revision: 471131
Mark devel/memleax LLD_UNSAFE same as devel/libunwind
/usr/bin/ld: error: cannot preempt symbol: _Ux86_64_create_addr_space
>>> defined in /usr/local/lib/libunwind-x86_64.so
>>> referenced by tmp.c
Submitted by: emaste