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

fusl/src/thread/__wait.c

Index: fusl/src/thread/__wait.c
diff --git a/fusl/src/thread/__wait.c b/fusl/src/thread/__wait.c
new file mode 100644
index 0000000000000000000000000000000000000000..dc33c1a30992e6c04e4482cef8a2f8279d18262a
--- /dev/null
+++ b/fusl/src/thread/__wait.c
@@ -0,0 +1,17 @@
+#include "pthread_impl.h"
+
+void __wait(volatile int *addr, volatile int *waiters, int val, int priv)
+{
+	int spins=100;
+	if (priv) priv = FUTEX_PRIVATE;
+	while (spins-- && (!waiters || !*waiters)) {
+		if (*addr==val) a_spin();
+		else return;
+	}
+	if (waiters) a_inc(waiters);
+	while (*addr==val) {
+		__syscall(SYS_futex, addr, FUTEX_WAIT|priv, val, 0) != -ENOSYS
+		|| __syscall(SYS_futex, addr, FUTEX_WAIT, val, 0);
+	}
+	if (waiters) a_dec(waiters);
+}