Inherit.xs, INLINE.h, and CPP.map were produced by cd'ing to this directory 
and running the Inline::C2XS function:

cpp2xs('Math::Geometry::Planar::GPC::Inherit', 'main');

For the purposes of providing a complete example of what is needed, I've 
included, in this directory (ie 'demos/cpp'), a corresponding pm file, a 
Makefile.PL, a MANIFEST, a README (this file) and a test file (test.pl).

The assumption is that you're using 'g++' as your cpp compiler. If that's not
the case then you need to first amend the 'CC' entry in the Makefile.PL
appropriately.

Then cd to the directory containing this file and run:

perl Makefile.PL
make test

You should even be able to then successfully run 'make install' - though,
given that this module doesn't really do anything useful, I don't know why
anyone would want to install it. It's also quite ludicrous to be creating
Inherit.pm in the Math::Geometry::Planar::GPC namespace.

Anyway, this demo works fine for me on Win32 using the MinGW's g++
compiler and MinGW-built perl 5.8.8.

Cheers,
Rob