I just figured this exact same problem out on my own.
The steps are:
- Locate md5.h on your system
- Set the CFLAGS environment variable to include that location
- Run cmusfm's configure and install process
If you use homebrew or macports you can execute the following to find the path to md5.h (respectively):
find /usr/local -name md5.h # brew find /opt/local -name md5.h # macports
You may also be able to use Finder or Spotlight to find md5.h.
Then do this to tell the compiler to look there:
export CFLAGS='-I/your/path/to/openssl/include'
For example, mine was
export CFLAGS='-I/usr/local/Cellar/openssl/1.0.2f/include'
Then rerun the configure script and make && make install. Good luck!