MinGW and Cygwin don't currently support weak function definitions. For these platforms, we have to make tf_getlongsimtime a strong symbol. It is unlikely a user will have defined their own function with this name - and anyway the VPI 1.0 interface was deprecated in 1364-2001 and removed in 1364-2005 so I wouldn't expect many of our users to be using it.
This patch should be applied to both devel and V0.9. No test suite changes (it fixes a failure in the VPI tests on these platforms).