[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/stdio/printf_count_output.cpp

@@ -0,0 +1,35 @@
+//
+// printf_count_output.cpp
+//
+//      Copyright (c) Microsoft Corporation.  All rights reserved.
+//
+// Defines the functions that control the enable state of %n.
+//
+#include <corecrt_internal_stdio.h>
+
+
+
+static UINT_PTR enable_percent_n = 0;
+
+
+
+// Enables or disables the %n format specifier for the printf family of functions.
+// Note the use of the __security_cookie:  if the static variable was set to a
+// known value, an attacker could potentially modify that value and then provide
+// a malicious %n specifier.  The cookie is or'ed with 1 becuase a cookie with a
+// value of zero is possible.
+extern "C" int __cdecl _set_printf_count_output(int const value)
+{
+    int const old = (enable_percent_n == (__security_cookie | 1));
+    enable_percent_n = (value ? (__security_cookie | 1) : 0);
+    return old;
+}
+
+
+
+// Tests whether the %n format specifier for the printf family of functions is
+// enabled.
+extern "C" int __cdecl _get_printf_count_output()
+{
+    return enable_percent_n == (__security_cookie | 1);
+}