[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/ismbspc.cpp

@@ -0,0 +1,53 @@
+/***
+*ismbspc.c - Test is character is whitespace (MBCS)
+*
+*       Copyright (c) Microsoft Corporation.  All rights reserved.
+*
+*Purpose:
+*       Test is character is whitespace (MBCS)
+*
+*******************************************************************************/
+#ifndef _MBCS
+    #error This file should only be compiled with _MBCS defined
+#endif
+
+#include <corecrt_internal_mbstring.h>
+#include <locale.h>
+
+/***
+* _ismbcspace - Test is character is whitespace (MBCS)
+*
+*Purpose:
+*       Test if the character is a whitespace character.
+*       Handles MBCS chars correctly.
+*
+*       Note:  Use test against 0x00FF instead of _ISLEADBYTE
+*       to ensure that we don't call SBCS routine with a two-byte
+*       value.
+*
+*Entry:
+*       unsigned int c = character to test
+*
+*Exit:
+*       Returns TRUE if character is whitespace, else FALSE
+*
+*Exceptions:
+*
+*******************************************************************************/
+
+extern "C" int __cdecl _ismbcspace_l(unsigned int const c, _locale_t const locale)
+{
+    _LocaleUpdate locale_update(locale);
+
+    if (c <= 0x00FF)
+    {
+        return _isspace_l(c, locale_update.GetLocaleT());
+    }
+
+    return __dcrt_multibyte_check_type(c, locale_update.GetLocaleT(), _SPACE, true);
+}
+
+extern "C" int __cdecl _ismbcspace(unsigned int const c)
+{
+    return _ismbcspace_l(c, nullptr);
+}