LibC: Implement wmemset

Author: https://github.com/timschumi
Commit: fa1208edfd
Pull-request: https://github.com/SerenityOS/serenity/pull/10298
Reviewed-by: https://github.com/bgianfo ✅

Userland/Libraries/LibC/wchar.cpp

@@ -393,4 +393,13 @@ wchar_t* wmemcpy(wchar_t* dest, const wchar_t* src, size_t n)
 
     return dest;
 }
+
+wchar_t* wmemset(wchar_t* wcs, wchar_t wc, size_t n)
+{
+    for (size_t i = 0; i < n; i++) {
+        wcs[i] = wc;
+    }
+
+    return wcs;
+}
 }