system.h (CONST_CAST2): Use C++ const_cast when compiled as C++

gcc/ChangeLog
	* system.h (CONST_CAST2): Use C++ const_cast when compiled as C++

From-SVN: r147928

gcc/ChangeLog

+2009-05-27  Tom Tromey  <tromey@redhat.com>
+
+	* system.h (CONST_CAST2): Use C++ const_cast when compiled as C++
+
 2009-05-27  Ian Lance Taylor  <iant@google.com>
 
 	* Makefile.in (LINKER, LINKER_FLAGS): Define.

gcc/system.h

@@ -786,6 +786,9 @@ extern void fancy_abort (const char *, int, const char *) ATTRIBUTE_NORETURN;
    change after the fact).  Beyond these uses, most other cases of
    using this macro should be viewed with extreme caution.  */
 
+#ifdef __cplusplus
+#define CONST_CAST2(TOTYPE,FROMTYPE,X) (const_cast<TOTYPE> (X))
+#else
 #if defined(__GNUC__) && GCC_VERSION > 4000
 /* GCC 4.0.x has a bug where it may ICE on this expression,
    so does GCC 3.4.x (PR17436).  */
@@ -793,6 +796,7 @@ extern void fancy_abort (const char *, int, const char *) ATTRIBUTE_NORETURN;
 #else
 #define CONST_CAST2(TOTYPE,FROMTYPE,X) ((TOTYPE)(FROMTYPE)(X))
 #endif
+#endif
 #define CONST_CAST(TYPE,X) CONST_CAST2(TYPE, const TYPE, (X))
 #define CONST_CAST_TREE(X) CONST_CAST(union tree_node *, (X))
 #define CONST_CAST_RTX(X) CONST_CAST(struct rtx_def *, (X))