[LIBCNTPR] Implement NT version of iswctype

Passes all ntdll wine tests.

sdk/lib/crt/string/iswctype_nt.c

@@ -0,0 +1,21 @@
+/*
+ * PROJECT:     ReactOS NT CRT library
+ * LICENSE:     MIT (https://spdx.org/licenses/MIT)
+ * PURPOSE:     Implementation of iswctype
+ * COPYRIGHT:   Copyright 2025 Timo Kreuzer <timo.kreuzer@reactos.org>
+ */
+
+#include <ctype.h>
+
+extern const unsigned short _wctype[];
+
+_Check_return_
+int
+__cdecl
+iswctype(wint_t _C, wctype_t _Type)
+{
+    if (_C <= 0xFF)
+        return (_wctype[_C + 1] & _Type);
+
+    return 0;
+}

sdk/lib/crt/string/string.cmake

@@ -3,7 +3,6 @@ list(APPEND LIBCNTPR_STRING_SOURCE
     string/_splitpath.c
     string/_wsplitpath.c
     string/ctype.c
-    string/iswctype.c
     string/is_wctype.c
     string/scanf.c
     string/strcspn.c
@@ -91,6 +90,7 @@ list(APPEND CRT_STRING_SOURCE
     string/_wcslwr_s.c
     string/_wsplitpath_s.c
     string/atof.c
+    string/iswctype.c
     string/mbstowcs_s.c
     string/strcoll.c
     string/strdup.c
@@ -111,6 +111,7 @@ list(APPEND CRT_STRING_ASM_SOURCE
 )
 
 list(APPEND LIBCNTPR_STRING_SOURCE
+    string/iswctype_nt.c
     string/mbstowcs_nt.c
     string/tolower_nt.c
     string/toupper_nt_mb.c