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

fusl/include/fmtmsg.h

+#ifndef _FMTMSG_H
+#define _FMTMSG_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define MM_HARD         1
+#define MM_SOFT         2
+#define MM_FIRM         4
+
+#define MM_APPL         8
+#define MM_UTIL         16
+#define MM_OPSYS        32
+
+#define MM_RECOVER      64
+#define MM_NRECOV       128
+
+#define MM_PRINT        256
+#define MM_CONSOLE      512
+
+#define MM_NULLMC       0L
+
+#define MM_HALT         1
+#define MM_ERROR        2
+#define MM_WARNING      3
+#define MM_INFO         4
+#define MM_NOSEV        0
+
+#define MM_OK           0
+#define MM_NOTOK        (-1)
+#define MM_NOMSG        1
+#define MM_NOCON        4
+
+#define MM_NULLLBL      ((char*)0)
+#define MM_NULLTXT      ((char*)0)
+#define MM_NULLACT      ((char*)0)
+#define MM_NULLTAG      ((char*)0)
+#define MM_NULLSEV      0
+
+int fmtmsg(long, const char *, int, const char *, const char *, const char *);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif