When running the tests for the clang python bindings on windows 7 (x64, clang built with MSVC 10). This failure does not occur on Linux (Mint 12, clang built with gcc 4.6.1)
I think it is an intentional inconsistency in the way Clang handles enums when generating code for enums.
If I remember correctly gcc defaults to unsigned while MSVC defaults to int; Clang then just emulate their behavior in an attempt to be as close as possible to the code they emit.
I do not know how to “force” the target triplet in python tests, but this is generally the way used to get a platform independent test.