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

fusl/src/ctype/iswalpha.c

Index: fusl/src/ctype/iswalpha.c
diff --git a/fusl/src/ctype/iswalpha.c b/fusl/src/ctype/iswalpha.c
new file mode 100644
index 0000000000000000000000000000000000000000..00f9d81f5a7899d4748d35457928e5d2a342d5c8
--- /dev/null
+++ b/fusl/src/ctype/iswalpha.c
@@ -0,0 +1,22 @@
+#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);