cmake: fix issue on mingw in SetInstallPath
cmake: use unix compilers on mingw
cmake: add some mingw resources

there are needed with revent w32-mingw32 versions. They are needed to create missing import libraries
cmake: fix external project building on win32

everything should compile fine on both mingw and msvc

v2: fixed a sh assignement error
desurium: add #ifdefs for mingw

in some cases we have to use the unix API, where mingw has not access to specific windows functions
in other cases we have to use other functions
common: add missing declarations on mingw
threads: add comment and disclude not understandbale code on mingw
cmake: add missed include directory on mingw in util
usercore: fix compile error on mingw
cmake: fix some mingw linking problems
util_bootloader: don't define things, which are already defined
util_bootloader: fix compile errors on mingw
utilcore: fix some mingw compile errors
utils: replace __uuid calls with UUID references
util: fix compile on mingw
cmake: enable tests on mingw
desura: some fixes on mingw
cmake: add UtilLinux_test only on UNIX plattforms
desura: use own bootloader on mingw
cmake: add desura_browserhost to win32 build