This makes it possible to locate system files provided by libretro cores, as
well as database and cheat files.
* gnu/packages/patches/retroarch-improved-search-paths.patch: Extend patch.
* gnu/packages/emulators.scm (retroarch-minimal) [native-search-paths]:
Register new search paths for the LIBRETRO_CHEATS_DIRECTORY,
LIBRETRO_DATABASE_DIRECTORY and LIBRETRO_SYSTEM_DIRECTORY variables.
Reviewed-by: Sou Bunnbu (宋文武) <iyzsong@member.fsf.org>
Change-Id: I48f9a92608c0e36922ce9dcc9bbb61d6ca915002