* Merged in non-PolyObjects related changes from ZDoom r2481, 2486 and 2487:

- Changed the four-byte fillers in asm_x86_64/tmap3.s from 0x88888888 to 0x44444444 because   newer version of gas complained about it.
- Made SBARINFO more tolerant of certain error conditions. (Why is there so much duplication of code? It felt like I was changing the same lines over and over and over.)
- Changed xtoviewangle[] calculation so that when it mirrors the array to the left half, it does not include xtoviewangle[centerx] in the mirroring so that the two columns at the center of the screen do not map to the same angle. (BTW, this array is only used for the sky drawing.)
* The PolyObjects changes from r2480, 2482, 2483 and 2485 are NOT ported! For this reason, the svnrevision.h file is left untouched at the moment.

git-svn-id: http://mancubus.net/svn/hosted/gzdoom/trunk@865 b0f79afe-0144-0410-b225-9a4edf0717df

src/r_plane.cpp

@@ -740,6 +740,10 @@ inline void R_MakeSpans (int x, int t1, int b1, int t2, int b2, void (*mapfunc)(
 // in the normal convention for patches, but uses color 0 as a transparent
 // color instead.
 //
+// Note that since ZDoom now uses color 0 as transparent for other purposes,
+// you can use normal texture transparency, so the distinction isn't so
+// important anymore, but you should still be aware of it.
+//
 //==========================================================================
 
 static FTexture *frontskytex, *backskytex;