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

fusl/src/stdio/swscanf.c

Index: fusl/src/stdio/swscanf.c
diff --git a/fusl/src/stdio/swscanf.c b/fusl/src/stdio/swscanf.c
new file mode 100644
index 0000000000000000000000000000000000000000..d893fbacf13c7c3340091e42313f3539bca71117
--- /dev/null
+++ b/fusl/src/stdio/swscanf.c
@@ -0,0 +1,15 @@
+#include <stdarg.h>
+#include <wchar.h>
+#include "libc.h"
+
+int swscanf(const wchar_t *restrict s, const wchar_t *restrict fmt, ...)
+{
+	int ret;
+	va_list ap;
+	va_start(ap, fmt);
+	ret = vswscanf(s, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+
+weak_alias(swscanf,__isoc99_swscanf);