You should be able to type make in the base directory, go make a
sandwich, and come back to a working meterpreter for Mac OS X and iOS
Once you've made changes and compiled a new .dylib, copy the
contents of the osx/ or ios/ directory into your Metasploit Framework's
data/osx/ directory. In Mac OS X you can do this automatically if
metasploit-framework and meterpreter live in the same place by running
make install