Create a module to find MinGW
Fix search paths for Iconv and Miniupnpc
Make the various COMPILE-variables internal
Fix library pre- and suffixes for cross compiling
Add modules for automatically building contribs
Fix the S2-directory path for windows builds
Actually use the contrib autobuild feature
do not include bzip2 sources

when compiling s25client and s25update
Build s25update with default settings
Fix WinAPI video driver installation
remove unneeded link libraries from s25client