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

fusl/src/network/socket.c

+#include <sys/socket.h>
+#include <fcntl.h>
+#include <errno.h>
+#include "syscall.h"
+
+int socket(int domain, int type, int protocol)
+{
+        int s = socketcall(socket, domain, type, protocol, 0, 0, 0);
+        if (s<0 && (errno==EINVAL || errno==EPROTONOSUPPORT)
+            && (type&(SOCK_CLOEXEC|SOCK_NONBLOCK))) {
+                s = socketcall(socket, domain,
+                        type & ~(SOCK_CLOEXEC|SOCK_NONBLOCK),
+                        protocol, 0, 0, 0);
+                if (s < 0) return s;
+                if (type & SOCK_CLOEXEC)
+                        __syscall(SYS_fcntl, s, F_SETFD, FD_CLOEXEC);
+                if (type & SOCK_NONBLOCK)
+                        __syscall(SYS_fcntl, s, F_SETFL, O_NONBLOCK);
+        }
+        return s;
+}