This is a collection of the files that I modified in order to get the GNU Multiple Precision Arithmetic Library (GMP) version 3.1.1 to compile on Windows 32. Please note that this port has no dependencies on third party software. Also, I have only tested it on a Windows XP machine with MS Visual Studio .NET 2003.
To compile it just copy the files provided here to the distribution directory of GMP 3.1.1 and overwrite the existing files there, then simply enter the directory and type nmake. If you don't use MS VS .NET 2003 you would have to change the related include line in the Makefile. There is no installation required, just put gmp.h to your include path and gmp.lib to your library path. When you are using it in MSVC++ to compile new programs don't forget to define NTRG_WIN32, include gmp.h and link against gmp.lib.
In the directory bin/ you can find a pre-compiled version.