[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/setbuf.cpp

@@ -0,0 +1,28 @@
+//
+// setbuf.cpp
+//
+//      Copyright (c) Microsoft Corporation.  All rights reserved.
+//
+// Defines setbuf(), which enables or disables buffering on a stream.
+//
+#include <corecrt_internal_stdio.h>
+
+
+
+// If the buffer is null, buffering is disabled for the stream.  If the buffer is
+// non-null, it must point to a buffer of BUFSIZ characters; the stream will be
+// configured to use that buffer.  The functionality of setbuf() is a strict
+// subset of the functionality of setvbuf().
+extern "C" void __cdecl setbuf(FILE* const stream, char* const buffer)
+{
+    _ASSERTE(stream != nullptr);
+
+    if (buffer == nullptr)
+    {
+        setvbuf(stream, nullptr, _IONBF, 0);
+    }
+    else
+    {
+        setvbuf(stream, buffer, _IOFBF, BUFSIZ);
+    }
+}