Full documentation about the compilers as well as documentation about programming for the Macintosh in general can be found online. CodeWarrior plugin compilers appear to be available from the site as well. You can use either MASM or TASM to assemble the generated file. If so, these early versions of Borland's Turbo C might be just the compilers you need. It also includes an installer for your applications.
Source code is also available.
CC65 A cross-compiler for the 6502 that is a derivative of the Small C compiler. As with all interpreters, it may be useful in debugging programs or learning the language. The compiler may be used to generate any sort of program, commercial or otherwise. It comes with the usual man pages as well as a Language Reference Manual and a Programmer's Guide. I have not used this port myself, but based on what I read, it appears that they have their own and so on.