luaconf.h builds the module search paths out of LUA_ROOT, which upstream
hardcodes to /usr/local, where nothing installs on OpenWrt. LUA_ROOT is
defined unconditionally, but the two macros it feeds, LUA_PATH_DEFAULT
and LUA_CPATH_DEFAULT, are both guarded with #if !defined and are the
only users of it, so set them in TARGET_CFLAGS and drop the patch.
The resulting paths are the ones the patch produced, so the interpreter
behaves exactly as before.
Signed-off-by: Alexandru Ardelean <alex@shruggie.ro>