Implement wcscat().

library/wchar_wcscat.c

@@ -35,11 +35,13 @@
 #include "wchar_headers.h"
 #endif /* _WCHAR_HEADERS_H */
 
+/* Implementation based on musl */
+
 /****************************************************************************/
 
 wchar_t *
 wcscat(wchar_t *dest, const wchar_t *src)
 {
-	/* ZZZ unimplemented */
-	return(NULL);
+	wcscpy(dest + wcslen(dest), src);
+	return dest;
 }