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

fusl/src/network/getsockopt.c

Index: fusl/src/network/getsockopt.c
diff --git a/fusl/src/network/getsockopt.c b/fusl/src/network/getsockopt.c
new file mode 100644
index 0000000000000000000000000000000000000000..28079d8c0cb60a4e4d810a49ca7b0992bc6d4d9f
--- /dev/null
+++ b/fusl/src/network/getsockopt.c
@@ -0,0 +1,7 @@
+#include <sys/socket.h>
+#include "syscall.h"
+
+int getsockopt(int fd, int level, int optname, void *restrict optval, socklen_t *restrict optlen)
+{
+	return socketcall(getsockopt, fd, level, optname, optval, optlen, 0);
+}