Merge the two relevant patches that we used to make 1.8.x work against recent
serf versions.

$ svn merge ^/subversion/branches/1.8.x-serf-1.3+-windows@1517123 -c 1517123
$ svn merge ^/subversion/branches/1.8.x-openssl-dirs@1535139 -c 1535139

* .
* build/generator/gen_win.py
  Merge r1517123 and r1535139.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.7.x-serf-1.3.x-Windows@1543442 13f79535-47bb-0310-9956-ffa450edef68