- here we have my second attempt at building a tool to build Makefiles for simple C projects,
  dating to 2016, written in Perl this time, also called mfbuild.

- it works just like the C version did way back in the 1990s, by determining which local .h
  files are included in a single main program, and assuming that if fred.h is included, and
  fred.c also exists, then they form a single 2-part module called fred, and hence fred.c
  should be analysed for which local .h files it includes, and fred.o will need to be linked
  with the main program, and so on.

- install it into TOOLDIR/bin by 'make install', complete with man page and standard
  all-project definitions

- note that there's little point in having both the c-version and this perl-version installed.
  Pick one:-)
