Correctly check the dependencies of MSYS env.
Set up configure include and lib path for building the package.
update a few more CMake scripts.
This commit was SVN r24663.
It's not possible to combine two shared libraries on Windows, so we have to do it a bit different. First generate a small event static library by just linking the object files, and link it into other libraries that needs the libevent API.
This commit was SVN r24039.
