Update the build to support new external-libs layout, and autoconf options to specify windows word size. Split make_windows_releases into multiple scripts.
git-svn-id: svn+q:///qpdf/trunk@869 71b93d88-0707-0410-a8cf-f5a4172ac649
git-svn-id: svn+q:///qpdf/trunk@837 71b93d88-0707-0410-a8cf-f5a4172ac649