Fix OpenGL V_DrawCroppedPatch (Fixes #452)

Closes #452

See merge request !1412

Remove all remaining traces of the following macros for the obsolete DOS port, which were missed previously:
* `DJGPP`
* `__DJGPP__`
* `DJGPPDOS`
* `PC_DOS`
* `WATTCP`

May get rid of `MSDOS` later once I get word on whether I should kill it or not

(Apparently Kart made this exact fix 2 years ago and it was never backported?)

Fix compile warning on Windows

See merge request !1426

More final tweaks for 2.2.9 I guess

See merge request !1417

Papersprite dropshadows no longer askance

Closes #409

See merge request !1408

Fix a few renderflags oversights in OpenGL

See merge request STJr/SRB2!1422

Fix for #422

Closes #422

See merge request !1425

Remove misplaced SetShader call in CompileShaders (Fixes #402)

Closes #402

See merge request !1423

Use double precision in R_StoreWallRange sloped seg culling calculations (Fixes #434)

Closes #434

See merge request !1424

Print a backtrace when SRB2 crashes in a Unix-like environment.

See merge request !1288

Fixes culling issues in CEZ2 skybox

Check if GME_VERSION is defined.

See merge request !1372

Fix CA_BOUNCE height when flipped (Fixes #428)

Closes #428

See merge request !1373

Disable pausing during score screens in marathon mode

See merge request STJr/SRB2!1416

Fix translation colormap cache rebuilding using the old translation enumerations (fixes #443, #449, #459)

Closes #443, #449, and #459

See merge request !1421

Fix thing scale mismatch in R_DrawVisSprite. (Fixes #458)

Closes #458

See merge request !1420

Revert "Merge branch 'player-speed' into 'next'"

Closes #466 and #471

See merge request !1418

This was causing a buffer underwrite too. Lovely.

Fix "implicit declaration of function 'DEH_TableCheck'" warning

See merge request !1419

Nice UDB config there, SRB2.

See merge request STJr/SRB2!1354

Dependency files

See merge request STJr/SRB2!1407