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

fusl/src/mq/mq_timedreceive.c

Index: fusl/src/mq/mq_timedreceive.c
diff --git a/fusl/src/mq/mq_timedreceive.c b/fusl/src/mq/mq_timedreceive.c
new file mode 100644
index 0000000000000000000000000000000000000000..2cef6a86bff8c99498fe62acbd3411be6e5a45e5
--- /dev/null
+++ b/fusl/src/mq/mq_timedreceive.c
@@ -0,0 +1,7 @@
+#include <mqueue.h>
+#include "syscall.h"
+
+ssize_t mq_timedreceive(mqd_t mqd, char *restrict msg, size_t len, unsigned *restrict prio, const struct timespec *restrict at)
+{
+	return syscall_cp(SYS_mq_timedreceive, mqd, msg, len, prio, at);
+}