When doing this during startup it can be done by regular cleanup measures.
This also moves two larger chunks of networking code out of game.cpp.
Nevertheless, the fact that enet is a very dirty library which directly depends on Windows types is a big problem because it bleeds Windows definitions everywhere thanks to poor abstraction in all relevant layers.
Note: enet uses 'malloc' and 'free' as field names in a struct - this does not work with any compiler using some sort of heap instrumentation that #defines these names!
This had to be changed to allow MSVC debug builds to compile again.
The EDuke32 and RedNukem frontends are working, Blood isn't yet.
Notes:
many of the CMake variables and its output still refer to zdoom. Before changing that I wanted to make sure to be able to commit something that works.
support code for Windows XP has been entirely removed. On Windows this will only target Vista and up.
the crc32.h header had to be renamed to deconflict from zlib.
several Windows API calls were changed to call the A-versions directly. Weirdly enough there were places that defined their parameters as T types but in a non-working way.
removed some remaining editor files and support for the native software rendering only Windows backend.
in a few simple cases, replaced 'char' with 'uint8_t'. The code as-is depends on chars being unsigned which is non-portable. This needs to be carefully reviewed.
