Created attachment 221424 [details] patch
The project switched to cmake and they didn't add support to build documentation to CMakeLists.txt, so DOCS/DOXYGEN options are removed.
Build and package info is available at https://gitlab.com/swills/freebsd-ports/pipelines/245954547
Committed.
A commit references this bug: Author: yuri Date: Sun Jan 24 01:07:03 UTC 2021 New revision: 562433 URL: https://svnweb.freebsd.org/changeset/ports/562433 Log: math/muparser: Update 2.2.5 -> 2.3.2 PR: 252546 Approved by: nivit (maintainer's timeout 14 days) Changes: head/math/muparser/Makefile head/math/muparser/distinfo head/math/muparser/pkg-descr head/math/muparser/pkg-plist