In my system, the tarball containing this file is /mingw/var/cache/mingw-get/packages/libintl-0.18.1.1-1-msys-1.0.17-dll-8.tar.lzma.
2012/10/23 John Brown <email@example.com>
I don't know why this is happening to you, but perhaps you can try
extracting the DLL manually. If the archive was downloaded, you should
find it at:
Well, this is the file that I have. Substitute your version.
It contains one file: bin/msys-intl-8.dll.