Added CLOCK_REALTIME to clock_gettime emulation.

deps/tinycthread.h

@@ -122,6 +122,7 @@ typedef int _tthread_clockid_t;
 /* Emulate clock_gettime */
 int _tthread_clock_gettime(clockid_t clk_id, struct timespec *ts);
 #define clock_gettime _tthread_clock_gettime
+#define CLOCK_REALTIME 0
 #endif