The topic came up before regarding static versus dynamic linking and how that might affect licensing issues. Was trying to think of some examples, but couldn't remember specifics at the time.
Ran across one yesterday where static and dynamic linking are treated differently by the license. If you supply all the source, it shouldn't be an issue. However, libgmp is typically linked with the mingw compiler, so everything you build with the compiler would need to conform with certain license restrictions. Here's the mention:
http://www.haskell.org/pipermail/glasgow-haskell-users/2002-May/003422.html