check if LUA field exists before accessing it
lauxlib.h: mark luaL_error as a REPORT function add check that LUA code can't access fields that don't exist in mapthing_t Closes #1168 (closed)
lauxlib.h: mark luaL_error as a REPORT function add check that LUA code can't access fields that don't exist in mapthing_t Closes #1168 (closed)