libstdc++: Remove noexcept from std::osyncstream::operator=

This should not be noexcept because its _M_syncbuf member has a
potentially-throwing move assignment operator. The noexcept was removed
by LWG 3867.

libstdc++-v3/ChangeLog:

	* include/std/syncstream (basic_osyncstream::operator=): Remove
	noexcept, as per LWG 3867.

(cherry picked from commit 67f5a8c802463228da7c7bb2ab100095217560a6)

diff --git a/libstdc++-v3/include/std/syncstream b/libstdc++-v3/include/std/syncstream
index 3788b71ecddc6f4dab535c5513624819307b156e..19cb581b7daa1399fdf3f2939eb0a8b23581c469 100644 (file)
--- a/libstdc++-v3/include/std/syncstream
+++ b/libstdc++-v3/include/std/syncstream
@@ -286,7 +286,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       ~basic_osyncstream() = default;
 
-      basic_osyncstream& operator=(basic_osyncstream&&) noexcept = default;
+      basic_osyncstream& operator=(basic_osyncstream&&) = default;
 
       syncbuf_type* rdbuf() const noexcept
       { return const_cast<syncbuf_type*>(&_M_syncbuf); }