[mtdewcmu]

make looks for [Mm]akefile if you run it with no arguments, but here it's being run recursively (or included). On OSX, filenames are case-insensitive, which could be a possible reason why it works for some people. On Linux, filenames are case sensitive.

[FreeFull]

That seems to be the case, since running file on one of the existing .o files says that they are Mach-O i386 objects. The readme doesn't mention OS X though, only Ubuntu