The new OpenSMTPD 7.5.0rc1 works well with LibreSSL on Slackware64
Linux.
My compile script uses CFLAGS and LDFLAGS like this:
CFLAGS="... -I/usr/include/libressl" \
LDFLAGS="-L/usr/lib64/libressl -lcrypto -lssl \
-Wl,-rpath=/usr/lib64/libressl" \
./configure \
...
It solves the git problem 1188,
"configure: error: Your LibreSSL headers do not match your library".
And it works even when I don't have LibreSSL installed and just have
OpenSSL 1 installed.
This version works on 32-bit Slackware:
CFLAGS="... -I/usr/include/libressl" \
LDFLAGS="-L/usr/lib/libressl -lcrypto -lssl \
-Wl,-rpath=/usr/lib/libressl" \
./configure \
...
Richard Narron