Thus said "Todd C. Miller" on Wed, 31 Jan 2018 14:11:09 -0700:
The OpenBSD C compiler does not look in /usr/local/include or
/usr/local/lib by default but the nmh port's Makefile does.
I should have cracked open the Makefile and I would have seen the
obvious CONFIGURE_ENV options being passed in.
CPPFLAGS="-I/usr/local/include" LDFLAGS="-L/usr/local/lib" ./configure
Yes, now it builds and the test passes, and now I see that
test/common.sh is actually ``built'' on demand from test/common.sh.in
with the rest of the build process so that it defaults ICONV_ENABLED
differently based on how it was configured. That answers my previous
question about how ICONV_ENABLED could ever be altered (it happens at
$ make TESTS=test/mhshow/test-charset check
make test/fakehttp test/fakepop test/fakesmtp test/getcanon test/getcwidth
test/getfullname test/runpty test/common.sh
`test/fakehttp' is up to date.
`test/fakepop' is up to date.
`test/fakesmtp' is up to date.
`test/getcanon' is up to date.
`test/getcwidth' is up to date.
`test/getfullname' is up to date.
`test/runpty' is up to date.
`test/common.sh' is up to date.
1 test passed
TAI64 timestamp: 400000005a73d21d