Add workaround for submodules that use legacy CMAKE variables

CMakeLists.txt

@@ -178,6 +178,9 @@ macro(yuzu_find_packages)
         endif()
         if (NOT ${PACKAGE_PREFIX}_FOUND)
             list(APPEND CONAN_REQUIRED_LIBS ${PACKAGE_CONAN})
+        else()
+            # Set a legacy findPackage.cmake style PACKAGE_LIBRARIES variable for subprojects that rely on this
+            set(${PACKAGE_PREFIX}_LIBRARIES "${PACKAGE_PREFIX}::${PACKAGE_PREFIX}")
         endif()
     endforeach()
     unset(FN_FORCE_REQUIRED)