Request: make coff2omf free

[torhu]

Frits van Bommel wrote:
  > Can't you just compile it with DMC? It shares the backend with DMD, so
> it should produce link-compatible output.

That's was my first idea, and I converted the makefile.  But there's 
some preprocessor stuff too that needs adjusting.  At that point i 
started looking for easier solutions.  So it's not 'just' compiling with 
DMC, I'm afraid.  I wish it was.

C libraries tend to have complicated build setups, that involve multiple 
makefiles, scripts, and elaborate use of the preprocessor to adapt code 
to various compilers.  AllegroGL is no exception.