Define CONSTEXPR macro and use it in vec.h.

2017-05-18  Martin Liska  <mliska@suse.cz>

	* ansidecl.h: Define CONSTEXPR macro.
2017-05-18  Martin Liska  <mliska@suse.cz>

	* vec.h (struct vnull): Use it.

From-SVN: r248205

gcc/ChangeLog

+2017-05-18  Martin Liska  <mliska@suse.cz>
+
+	* vec.h (struct vnull): Use it.
+
 2017-05-18  Jan Hubicka  <hubicka@ucw.cz>
 
 	* ipa-inline-analysis.c (predicate_conditions): Move to ipa-inline.h

gcc/vec.h

@@ -416,10 +416,7 @@ struct GTY((user)) vec
 struct vnull
 {
   template <typename T, typename A, typename L>
-#if __cpp_constexpr >= 200704
-  constexpr
-#endif
-  operator vec<T, A, L> () { return vec<T, A, L>(); }
+  CONSTEXPR operator vec<T, A, L> () { return vec<T, A, L>(); }
 };
 extern vnull vNULL;
 

include/ChangeLog

+2017-05-18  Martin Liska  <mliska@suse.cz>
+
+	* ansidecl.h: Define CONSTEXPR macro.
+
 2017-04-04  Jonathan Wakely  <jwakely@redhat.com>
 
 	* ansidecl.h (ATTRIBUTE_PACKED): Fix typo in comment.

include/ansidecl.h

@@ -313,6 +313,12 @@ So instead we use the macro below and test it against specific values.  */
 #define ENUM_BITFIELD(TYPE) unsigned int
 #endif
 
+#if __cpp_constexpr >= 200704
+#define CONSTEXPR constexpr
+#else
+#define CONSTEXPR
+#endif
+
 /* C++11 adds the ability to add "override" after an implementation of a
    virtual function in a subclass, to:
      (A) document that this is an override of a virtual function