The "testStartStopWait" unit test is unreliably failing on mac,
for some time already. See bug #3786.
Having the unittest fail unreliably doesn't help anybody but mostly
inhibits the main feature of travis builds: to test PRs for regressions.
Therefore, disable the specific unit test for until bug #3786
is fixed.
void TestThreading::runTests(IGameDef *gamedef)
{
+#if !(defined(__MACH__) && defined(__APPLE__))
TEST(testStartStopWait);
+#endif
TEST(testThreadKill);
TEST(testAtomicSemaphoreThread);
}