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

fusl/src/ctype/iswalpha.c

+#include <wctype.h>
+#include "libc.h"
+
+static const unsigned char table[] = {
+#include "alpha.h"
+};
+
+int iswalpha(wint_t wc)
+{
+        if (wc<0x20000U)
+                return (table[table[wc>>8]*32+((wc&255)>>3)]>>(wc&7))&1;
+        if (wc<0x2fffeU)
+                return 1;
+        return 0;
+}
+
+int __iswalpha_l(wint_t c, locale_t l)
+{
+        return iswalpha(c);
+}
+
+weak_alias(__iswalpha_l, iswalpha_l);