🚀 go-pugleaf

I haven't tried using RCS with Modula-2 source, but I have
worked out a method for using make.

Put implementation and program modules in .mod files and
definition modules in .def files.  Each .mod file will
generate a .o file; each .def file will generate a .sym
file.  The .sym files have 0 bytes and are used only to
communicate dependencies.  Every .sym file depends on
the corresponding .def file and the .sym files of any
imported modules.  Make it with touch(1).  Every .o file
depends on the corresponding .mod file and the .sym files
of any imported modules.  If it is an implementation module
is also depends on its own .sym file.

Using .sym files forces make to calculate the transitive
closure of the imports relation.  This way, if A imports B
and B (def) imports C, you don't have to have A.o depend on C.def.
Instead, A.o depends on B.sym, which depends on C.sym, which
depends on C.def.

Rich