Use *NSYNC for POSIX threads locking APIs

Condition variables, barriers, and r/w locks now work very well.

third_party/nsync/time.h

@@ -0,0 +1,53 @@
+#ifndef NSYNC_TIME_H_
+#define NSYNC_TIME_H_
+#include "libc/calls/struct/timespec.h"
+#if !(__ASSEMBLER__ + __LINKER__ + 0)
+COSMOPOLITAN_C_START_
+
+#define NSYNC_TIME_SEC(t)  ((t).tv_sec)
+#define NSYNC_TIME_NSEC(t) ((t).tv_nsec)
+#define NSYNC_TIME_STATIC_INIT(t, ns) \
+  { (t), (ns) }
+
+/* The type nsync_time represents the interval elapsed between two
+   moments in time. Often the first such moment is an address-space-wide
+   epoch, such as the Unix epoch, but clients should not rely on the
+   epoch in one address space being the same as that in another.
+   Intervals relative to the epoch are known as absolute times. */
+typedef struct timespec nsync_time;
+
+/* A deadline infinitely far in the future. */
+extern const nsync_time nsync_time_no_deadline;
+
+/* The zero delay, or an expired deadline. */
+extern const nsync_time nsync_time_zero;
+
+/* Return the current time since the epoch.  */
+#define nsync_time_now() _timespec_real()
+
+/* Sleep for the specified delay. Returns the unslept time which may be
+   non-zero if the call was interrupted. */
+nsync_time nsync_time_sleep(nsync_time delay);
+
+/* Return a+b */
+#define nsync_time_add(a, b) _timespec_add(a, b)
+
+/* Return a-b */
+#define nsync_time_sub(a, b) _timespec_sub(a, b)
+
+/* Return +ve, 0, or -ve according to whether a>b, a==b, or a<b. */
+#define nsync_time_cmp(a, b) _timespec_cmp(a, b)
+
+/* Return the specified number of milliseconds as a time. */
+#define nsync_time_ms(a) _timespec_frommillis(a)
+
+/* Return the specified number of microseconds as a time. */
+#define nsync_time_us(a) _timespec_frommicros(a)
+
+/* Return an nsync_time constructed from second and nanosecond
+   components */
+#define nsync_time_s_ns(s, ns) ((nsync_time){(int64_t)(s), (unsigned)(ns)})
+
+COSMOPOLITAN_C_END_
+#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
+#endif /* NSYNC_TIME_H_ */