Remove the .rc file, fix SOVERSION of vtkzlib.
The windres compiler for mingw is broken (it cannot handle paths with spaces), so the best solution is to remove the .rc file completely since it wasn't used before the recent update to zlib-1.2.8.
The windres compiler for mingw is broken (it cannot handle paths with spaces), so the best solution is to remove the .rc file completely since it wasn't used before the recent update to zlib-1.2.8.