In Xcode 8 (more or less mandatory after upgrading to Sierra), Apple added support for `clock_gettime(CLOCK_MONOTONIC, &ts)`, which is not bad in itself.
Unfortunately, with this addition, a QEMU built on 10.12 runs **only** on 10.12; on previous versions it fails with something like: ``` $ ./qemu-system-gnuarmeclipse --version dyld: lazy symbol binding failed: Symbol not found: _clock_gettime Referenced from: /Applications/GNU ARM Eclipse/QEMU/2.6.0-201610170917-dev/bin/./qemu-system-gnuarmeclipse (which was built for Mac OS X 10.12) Expected in: /usr/lib/libSystem.B.dylib ``` The explanation is simple, for previous versions `_clock_gettime` is not available in the system library. Apple does some tricks with macros in `time.h` to specify that the definitions were introduced in 10.12, but QEMU uses only `#ifdef CLOCK_MONOTONIC` to select the use of `clock_gettime()`. Until a more elaborate solution will be considered, my workaround was to replace `#ifdef CLOCK_MONOTONIC` with `#if defined(CLOCK_MONOTONIC) && !defined(__APPLE__)` and so avoid references to `clock_gettime()`. Regards, Liviu
