Please exp-run this patch: https://people.freebsd.org/~bdrewery/patches/configure-job-server.diff It adds a --enable-jobserver=${MAKE_JOBS_NUMBER}, if supported. The problem is described more at https://svnweb.freebsd.org/changeset/ports/435782
Exp-run looks fine.
A commit references this bug: Author: bdrewery Date: Mon Mar 13 17:47:17 UTC 2017 New revision: 436097 URL: https://svnweb.freebsd.org/changeset/ports/436097 Log: GNU_CONFIGURE: Fix ax_am_jobserver usage to respect MAKE_JOBS_NUMBER. PR: 217670 [exp-run] With hat: portmgr Changes: head/Mk/bsd.port.mk head/databases/libmemcached/Makefile