SDL2, windows: update to latest official 2.30.7 version.
Reset r_skyfog between maps
gl_sky.c: include malloc.h in watcom builds for alloca()
Update ChangeLog for 4.6.1 changes so far
update copyright years of the sources touched after the last time.
Update ChangeLog for 4.6.1 changes so far
use response files with msvc and watcom makefiles.
conditionalize use of __forceinline