Add a "fork" of musl as //fusl.

fusl/src/thread/__timedwait.c

Index: fusl/src/thread/__timedwait.c
diff --git a/fusl/src/thread/__timedwait.c b/fusl/src/thread/__timedwait.c
new file mode 100644
index 0000000000000000000000000000000000000000..13d8465a450552bf418f05ac06a3d81176c5b118
--- /dev/null
+++ b/fusl/src/thread/__timedwait.c
@@ -0,0 +1,46 @@
+#include <pthread.h>
+#include <time.h>
+#include <errno.h>
+#include "futex.h"
+#include "syscall.h"
+#include "pthread_impl.h"
+
+int __pthread_setcancelstate(int, int *);
+int __clock_gettime(clockid_t, struct timespec *);
+
+int __timedwait_cp(volatile int *addr, int val,
+	clockid_t clk, const struct timespec *at, int priv)
+{
+	int r;
+	struct timespec to, *top=0;
+
+	if (priv) priv = 128;
+
+	if (at) {
+		if (at->tv_nsec >= 1000000000UL) return EINVAL;
+		if (__clock_gettime(clk, &to)) return EINVAL;
+		to.tv_sec = at->tv_sec - to.tv_sec;
+		if ((to.tv_nsec = at->tv_nsec - to.tv_nsec) < 0) {
+			to.tv_sec--;
+			to.tv_nsec += 1000000000;
+		}
+		if (to.tv_sec < 0) return ETIMEDOUT;
+		top = &to;
+	}
+
+	r = -__syscall_cp(SYS_futex, addr, FUTEX_WAIT|priv, val, top);
+	if (r == ENOSYS) r = -__syscall_cp(SYS_futex, addr, FUTEX_WAIT, val, top);
+	if (r != EINTR && r != ETIMEDOUT && r != ECANCELED) r = 0;
+
+	return r;
+}
+
+int __timedwait(volatile int *addr, int val,
+	clockid_t clk, const struct timespec *at, int priv)
+{
+	int cs, r;
+	__pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+	r = __timedwait_cp(addr, val, clk, at, priv);
+	__pthread_setcancelstate(cs, 0);
+	return r;
+}