* Forward declaration of structures in headers where possible
* Use M_snprinf instead of sprintf
* Remove D_INTMAX D_INTMIN
* Don't change libtextscreen files
* Add miniz and win32 include directories
* implement M_getenv for compatibility with non-Latin paths on Windows
* use regular wcslen
SDL_wcslen is undocumented
* fix memory leak
* cache the `wenv == NULL` case
* add OPL emulation from Chocolate Doom
* get rid of detect_voices
* split the SDL music backend into a separate source file
* add post-realloc() check
* add OPL emulation copyright holders
* add some minimal comments
* add config variable and menu item
* sacrifice PCX format screenshot menu entry