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

fusl/include/sys/un.h

Index: fusl/include/sys/un.h
diff --git a/fusl/include/sys/un.h b/fusl/include/sys/un.h
new file mode 100644
index 0000000000000000000000000000000000000000..7494f1a382ed0164f6e7dc35520e19d30e33c6bf
--- /dev/null
+++ b/fusl/include/sys/un.h
@@ -0,0 +1,32 @@
+#ifndef	_SYS_UN_H
+#define	_SYS_UN_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <features.h>
+
+#define __NEED_sa_family_t
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+#define __NEED_size_t
+#endif
+
+#include <bits/alltypes.h>
+
+struct sockaddr_un
+{
+	sa_family_t sun_family;
+	char sun_path[108];
+};
+
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+size_t strlen(const char *);
+#define SUN_LEN(s) (2+strlen((s)->sun_path))
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif