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

fusl/src/locale/wcsxfrm.c

Index: fusl/src/locale/wcsxfrm.c
diff --git a/fusl/src/locale/wcsxfrm.c b/fusl/src/locale/wcsxfrm.c
new file mode 100644
index 0000000000000000000000000000000000000000..0a0b776dadf46aa65c91303dd43776b22c158679
--- /dev/null
+++ b/fusl/src/locale/wcsxfrm.c
@@ -0,0 +1,24 @@
+#include <wchar.h>
+#include <locale.h>
+#include "locale_impl.h"
+#include "libc.h"
+
+/* collate only by code points */
+size_t __wcsxfrm_l(wchar_t *restrict dest, const wchar_t *restrict src, size_t n, locale_t loc)
+{
+	size_t l = wcslen(src);
+	if (l < n) {
+		wmemcpy(dest, src, l+1);
+	} else if (n) {
+		wmemcpy(dest, src, n-1);
+		dest[n-1] = 0;
+	}
+	return l;
+}
+
+size_t wcsxfrm(wchar_t *restrict dest, const wchar_t *restrict src, size_t n)
+{
+	return __wcsxfrm_l(dest, src, n, CURRENT_LOCALE);
+}
+
+weak_alias(__wcsxfrm_l, wcsxfrm_l);