libstdc++: avoid -Wzero-as-null-pointer-constant

libstdc++-v3/ChangeLog:

	* include/std/coroutine (coroutine_handle): Use nullptr instead of
	0 as initializer for _M_fr_ptr.

diff --git a/libstdc++-v3/include/std/coroutine b/libstdc++-v3/include/std/coroutine
index 908c1178a1497724e873935008d800b2a7cbb919..ccd016b255eba351dde9758d9f0257cf473466c1 100644 (file)
--- a/libstdc++-v3/include/std/coroutine
+++ b/libstdc++-v3/include/std/coroutine
@@ -99,7 +99,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     {
     public:
       // [coroutine.handle.con], construct/reset
-      constexpr coroutine_handle() noexcept : _M_fr_ptr(0) {}
+      constexpr coroutine_handle() noexcept : _M_fr_ptr(nullptr) {}
 
       constexpr coroutine_handle(std::nullptr_t __h) noexcept
        : _M_fr_ptr(__h)