-lm is needed for these tests on Linux, but the lit config for this package automatically adds it for Linux and excludes it for Windows. So we should be able to get these tests running again by just dropping -lm and let the lit config add it when possible.
I was under the impression that -lm worked across platforms because it exists in other tests without any 'UNSUPPORTED: windows' commands (e.g. see divsc3_test.c), but those are actually excluded because they 'REQUIRES: c99-complex' which is excluded from windows platforms (also by the local lit config).
I don't have easy access to a windows machine to verify this patch, but I can trigger a build bot run on clang-x64-ninja-win7 shortly after submitting.