diff --git a/include/ChangeLog b/include/ChangeLog
index 93308e863..1af04e80b 100644
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,3 +1,7 @@
+2009-06-02  Ian Lance Taylor  <iant@google.com>
+
+	* ansidecl.h (EXPORTED_CONST): Define.
+
 2009-05-31  Ian Lance Taylor  <iant@google.com>
 
 	* ansidecl.h: Add extern "C" when compiling with C++.  Treat C++
diff --git a/include/ansidecl.h b/include/ansidecl.h
index c83b8c039..f9864cd38 100644
--- a/include/ansidecl.h
+++ b/include/ansidecl.h
@@ -395,6 +395,18 @@ So instead we use the macro below and test it against specific values.  */
 #define __extension__
 #endif
 
+/* This is used to declare a const variable which should be visible
+   outside of the current compilation unit.  Use it as
+     EXPORTED_CONST int i = 1;
+   This is because the semantics of const are different in C and C++.
+   "extern const" is permitted in C but it looks strange, and gcc
+   warns about it when -Wc++-compat is not used.  */
+#ifdef __cplusplus
+#define EXPORTED_CONST extern const
+#else
+#define EXPORTED_CONST const
+#endif
+
 #ifdef __cplusplus
 }
 #endif