Fix Windows project file generator to not exclude .c files
generated by Swig from the build.

* build/generator/gen_win.py (GeneratorBase.__init__):
   Construct a set of all private include files that were explicitly
   listed in build.conf.
  (WinGeneratorBase.get_proj_sources): Only exclude from build those
   dependencies that appear in the exclude list.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1491788 13f79535-47bb-0310-9956-ffa450edef68