[01/23] vec: Silence clang warning

[Richard Sandiford via Gcc-patches]

I noticed during compatibility testing that clang warns that this
operator won't be implicitly const in C++14 onwards.

gcc/
        * vec.h (vnull::operator vec<T, A, L>): Make const.
---
 gcc/vec.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/vec.h b/gcc/vec.h
index 14d77e87342..f02beddc975 100644
--- a/gcc/vec.h
+++ b/gcc/vec.h
@@ -540,7 +540,7 @@ vec_copy_construct (T *dst, const T *src, unsigned n)
 struct vnull
 {
   template <typename T, typename A, typename L>
-  CONSTEXPR operator vec<T, A, L> () { return vec<T, A, L>(); }
+  CONSTEXPR operator vec<T, A, L> () const { return vec<T, A, L>(); }
 };
 extern vnull vNULL;
 
-- 
2.17.1