In the windows project generator: resolve a regression in linking swig
libraries when compiling subversion to shared libraries.

Libraries of dependency projects are not available when the
project is turned into a shared library.

* build/generator/gen_win.py
  (get_win_lib_dirs,
   get_win_libs): Link to language specific libraries (E.g. perl516.lib)
     from swig project instances for specific languages


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1544171 13f79535-47bb-0310-9956-ffa450edef68