[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/mbstring/mbccpy.cpp

@@ -0,0 +1,48 @@
+/***
+*mbccpy.c - Copy one character  to another (MBCS)
+*
+*       Copyright (c) Microsoft Corporation. All rights reserved.
+*
+*Purpose:
+*       Copy one MBCS character to another (1 or 2 bytes)
+*
+*******************************************************************************/
+
+#include <corecrt_internal_mbstring.h>
+#include <locale.h>
+
+/***
+* _mbccpy - Copy one character to another (MBCS)
+*
+*Purpose:
+*       Copies exactly one MBCS character from src to dst.  Copies _mbclen(src)
+*       bytes from src to dst.
+*
+*Entry:
+*       unsigned char *dst = destination for copy
+*       unsigned char *src = source for copy
+*
+*Exit:
+*
+*Exceptions:
+*       Input parameters are validated. Refer to the validation section of the function.
+*
+*******************************************************************************/
+
+extern "C" void __cdecl _mbccpy_l(
+        unsigned char *dst,
+        const unsigned char *src,
+        _locale_t plocinfo
+        )
+{
+    /* _mbccpy_s_l sets errno */
+    _mbccpy_s_l(dst, 2, nullptr, src, plocinfo);
+}
+
+extern "C" void (__cdecl _mbccpy)(
+        unsigned char *dst,
+        const unsigned char *src
+        )
+{
+    _mbccpy_s_l(dst, 2, nullptr, src, nullptr);
+}