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
cd nmh/
cat VERSION
1.7+dev
./autogen.sh
./configure
make
make check
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All 117 tests passed
(1 test was not run)
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