Use the lua version selected by lua eclass

--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -188,7 +188,11 @@ if (SOL2_IS_TOP_LEVEL AND (SOL2_DO_TESTS OR SOL2_DO_EXAMPLES))
 
 	string(TOLOWER ${SOL2_LUA_VERSION} NORMALIZED_LUA_VERSION)
 	# Find way to get Lua: build if requested, or attempt to build if no matching version is found
-	if (SOL2_BUILD_LUA)
+	if (TRUE)
+		find_package(PkgConfig REQUIRED)
+		pkg_check_modules(LUA REQUIRED lua IMPORTED_TARGET)
+		add_library(Lua::Lua ALIAS PkgConfig::LUA)
+	elseif (SOL2_BUILD_LUA)
 		find_package(LuaBuild REQUIRED COMPONENTS ${SOL2_LUA_VERSION})
 	elseif (NOT SOL2_LUA_VERSION)
 		find_package(LuaBuild REQUIRED)