Not a git user, so the problem could be on my end as I'm not getting a version that matches 1.7.1 (or newer). If I do the commands below, it compiles and tests cleanly (but again, I'm not sure I'm getting the right branch).
Ubuntu 20.04 git clone -b master git://git.savannah.nongnu.org/nmh.git cd nmh/ cat VERSION 1.7+dev ./autogen.sh ./configure make make check ==================== All 117 tests passed (1 test was not run) ====================