Move syncqt execution to build time to allow parallel execution for better performance

Currently syncqt is ran for each module at configure time, which means each reconfigure takes a longer time than necessary.

Consider moving syncqt execution to build time (make / jom), which allows it to be executed in parallel for different modules.

Also consider running it only once, and then the developer would have to rerun it somehow manually when changing header files. But we save time on incremental builds then.