lib: luajit: only require a C compiler

Upstream: zhaozg/luajit-cmake#17
Signed-off-by: Thomas Devoogdt <thomas@devoogdt.com>

Author: ThomasDevoogdt

lib/luajit-cmake/CMakeLists.txt

@@ -13,7 +13,7 @@ endif()
 
 get_directory_property(hasParent PARENT_DIRECTORY)
 if(LUAJIT_DIR)
-  project(luajit)
+  project(luajit LANGUAGES C)
   include(LuaJIT.cmake)
   if (hasParent)
     set(LUA_TARGET $<TARGET_FILE:luajit> PARENT_SCOPE)
@@ -24,7 +24,7 @@ if(LUAJIT_DIR)
     endif()
   endif()
 elseif(LUA_DIR)
-  project(lua)
+  project(lua LANGUAGES C)
   include(lua.cmake)
   if (hasParent)
     set(LUA_TARGET $<TARGET_FILE:lua> PARENT_SCOPE)