In v0.9.0rc2-4332-g8f0d79e the src/test/scheduler_tests.cpp test was disabled, but it was done in such a way as to define a function that then was no longer used, leading to this warning under at least my GCC 4.9.2-10:
test/scheduler_tests.cpp:32:13: warning: ‘void
scheduler_tests::MicroSleep(uint64_t)’ defined but not used
[-Wunused-function]
Fix this by just moving the "#if 0" a few lines up so that it also defines out a function used only by this test.