GMP dll for windows: linking errors

[Lesley MacPherson]

I am trying to build a GMP dll for use in Windows.  I am following the
instructions at
http://home.in.tum.de/~drost/old/howto-compile-gmp-with-vcpp.html
(which are for GMP-4.0.1).  I am using GMP-4.1.2 and have had to make a
few minor changes in order to get the code to compile.

Everything is fine till I get to the linking stage, where I get a few
unresolved external symbol errors for _vsnprintf, _snprintf, _strnlen, and
__imp__MessageBoxA@16.  At least two of these (_vsnprintf and _snprintf)
are supposed to be in libc.lib, which is included in my project workspace.

I used cygwin to generate the gmp.h and config.h files as described on the
link above.  I have heard of people using MinGW instead.  Any thoughts on
which is better (cygwin or MinGW) and instructions on how to create a dll
using MinGW?

Thanks,
Lesley