We don’t support FreePBX here. Those files are part of the source tree for Asterisk. You wil have them if you build Asterisk from source. I believe FreePBX is supplied with a pre-compiled binary, and not even the build configuration file, which you will need if you want to rebuild Asterisk in a FreePBX type configuration. I think you may need them to compile most add in modules, as I think some debugging options involve inline code.
As already noted, you wouldn’t normally run make explicitly on a module, althout it is possible that you do have to for third party code.