A thought about the current error building Gem on MinGW, perhaps it is because ./configure is detecting libdl, which MinGW has, but the libdl code doesn't work for Gem on MinGW. This is similar to what patco was sorting out with pure-data on MinGW. So something like this:
http://www.trilithium.com/johan/2004/12/problem-with-dlsym/
.hc
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