[UCRT] Import Microsoft.Windows.SDK.CRTSource version 10.0.22621.3

Imported from https://www.nuget.org/packages/Microsoft.Windows.SDK.CRTSource/10.0.22621.3
License: MIT

sdk/lib/ucrt/string/wcscat.cpp

@@ -0,0 +1,38 @@
+//
+// wcscat.cpp
+//
+//      Copyright (c) Microsoft Corporation.  All rights reserved.
+//
+// Defines wcscat(), which concatenates (appends) a copy of the source string to
+// the end of the destination string.
+//
+// This function assumes that the destination buffer is sufficiently large to
+// store the appended string.
+//
+#include <string.h>
+
+
+
+#if defined _M_X64 || defined _M_IX86 || defined _M_ARM || defined _M_ARM64
+    #pragma warning(disable:4163)
+    #pragma function(wcscat)
+#endif
+
+
+
+extern "C" wchar_t * __cdecl wcscat(
+    wchar_t*       const destination,
+    wchar_t const*       source
+    )
+{
+    wchar_t* destination_it = destination;
+
+    // Find the end of the destination string:
+    while (*destination_it)
+        ++destination_it;
+
+    // Append the source string to the destination string:
+    while ((*destination_it++ = *source++) != L'\0') { }
+
+    return destination;
+}