The libraries updated in this commit were built with a set of scripts:
https://gist.github.com/sfan5/780c24313c164d34634e18677683b9a3
Building new library versions or just using a different MinGW version
is now way easier. This means Windows builds no longer need to use
ancient library versions just because nobody knows how to build them.
Instead of trying to manually parse the output of 'git show' which can be different across different git configurations, properly use the 'git rev-parse' command that is intended for this purpose.
* CURL support
* only download packages if they don't exist
* fixed download links (libvorbis and libogg)
* manual downloading if automatic downloading fails (only minetest and minetest_game)
* mingwm10.dll and openal_stripped.zip are downloaded automatically
