Import stringize_macros from Chromium.
Committing the originals to make further reviews cleaner.
TBR=bjornv
BUG=webrtc:1395
Review URL: https://webrtc-codereview.appspot.com/1106005
git-svn-id: http://webrtc.googlecode.com/svn/trunk@3509 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/system_wrappers/interface/stringize_macros.h b/webrtc/system_wrappers/interface/stringize_macros.h
new file mode 100644
index 0000000..d4e2707
--- /dev/null
+++ b/webrtc/system_wrappers/interface/stringize_macros.h
@@ -0,0 +1,31 @@
+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// This file defines preprocessor macros for stringizing preprocessor
+// symbols (or their output) and manipulating preprocessor symbols
+// that define strings.
+
+#ifndef BASE_STRINGS_STRINGIZE_MACROS_H_
+#define BASE_STRINGS_STRINGIZE_MACROS_H_
+
+#include "build/build_config.h"
+
+// This is not very useful as it does not expand defined symbols if
+// called directly. Use its counterpart without the _NO_EXPANSION
+// suffix, below.
+#define STRINGIZE_NO_EXPANSION(x) #x
+
+// Use this to quote the provided parameter, first expanding it if it
+// is a preprocessor symbol.
+//
+// For example, if:
+// #define A FOO
+// #define B(x) myobj->FunctionCall(x)
+//
+// Then:
+// STRINGIZE(A) produces "FOO"
+// STRINGIZE(B(y)) produces "myobj->FunctionCall(y)"
+#define STRINGIZE(x) STRINGIZE_NO_EXPANSION(x)
+
+#endif // BASE_STRINGS_STRINGIZE_MACROS_H_