Created attachment 208201 [details] patch Upstream PR: https://github.com/lammps/lammps/pull/1483 Don't set BUILD_OMP. libomp is correctly found and used when building with clang anyway.
Now see D21994.
A commit references this bug: Author: pkubaj Date: Thu Nov 28 14:20:18 UTC 2019 New revision: 518579 URL: https://svnweb.freebsd.org/changeset/ports/518579 Log: science/lammps: fix build on GCC architectures Don't enable OpenMP everywhere, it causes an error with GCC, reported on https://github.com/lammps/lammps/pull/1483 This requires some hackery with ports not supporting options for specific compilers. OPENMP flag has removed option helpers due to them not being respected otherwise. PR: 241156 Approved by: yuri (maintainer, earlier versior), tcberner (mentor, earlier version) Differential Revision: https://reviews.freebsd.org/D21994 Changes: head/science/lammps/Makefile