Bill Hoffman authored Sep 10, 2015 and Brad King committed Sep 14, 2015

With 64-bit Windows builds, there is no need to remove the leading
underscore from all the symbols.  This is because it does not have one
in the .obj file unless it is really in the name.  This did not cause
any trouble until VS 2015 which has some system functions that have a
leading underscore that end up in the .def file.