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

fusl/src/errno/strerror.c

+#include <errno.h>
+#include <string.h>
+#include "locale_impl.h"
+#include "libc.h"
+
+#define E(a,b) ((unsigned char)a),
+static const unsigned char errid[] = {
+#include "__strerror.h"
+};
+
+#undef E
+#define E(a,b) b "\0"
+static const char errmsg[] =
+#include "__strerror.h"
+;
+
+char *__strerror_l(int e, locale_t loc)
+{
+        const char *s;
+        int i;
+        /* mips has one error code outside of the 8-bit range due to a
+         * historical typo, so we just remap it. */
+        if (EDQUOT==1133) {
+                if (e==109) e=-1;
+                else if (e==EDQUOT) e=109;
+        }
+        for (i=0; errid[i] && errid[i] != e; i++);
+        for (s=errmsg; i; s++, i--) for (; *s; s++);
+        return (char *)LCTRANS(s, LC_MESSAGES, loc);
+}
+
+char *strerror(int e)
+{
+        return __strerror_l(e, CURRENT_LOCALE);
+}
+
+weak_alias(__strerror_l, strerror_l);