Merge branch 'upstream/next' into zarrotsu_vanillamerge

# Conflicts:
#	src/Makefile
#	src/doomdef.h
#	src/hardware/hw_main.c
#	src/p_mobj.c
#	src/p_user.c
#	src/r_segs.c
#	src/sdl/i_video.c
#	src/win32/win_sys.c