games/darkplaces: the port had been updated and cleaned up (+)
- Update to 20180412beta1 penultimate snapshot, the very latest one had introduced too many changes which e.g. broke dedicated server
- Drop needless zip:infozip dependency, set USE_XORG more discretely
- Follow the defaults and link to libjpeg the usual way rather than load it at run-time with dlopen(3)
- Target `sdl-release' is spelled the same, regardless of the used SDL version
- Remove SSE port option: upstream makefile logic enables it for x86 CPUs; it's safe to assume that all modern x86 CPUs would support these instructions
- Amend patches and remove `post-patch' target (patching makefiles for LOCALBASE with sed(1) is bogus in the first place as it is passed on the MAKE_ENV and thus propagated down to inner makes)
- Do not try to use unsupported `-fno-signaling-nans' compiler flag
- Define LICENSE (GPLv2 or later) and assume port's maintainership
PR: 259123