libstdc++: Remove noexcept from syncbuf::swap (LWG 3498)

The proposed resolution for the inconsistent noexcept-specifiers in the
spec is to remove it from bto hthe assignment operator and swap.

libstdc++-v3/ChangeLog:

	* include/std/syncstream (basic_syncbuf::swap()): Remove
	noexcept, as per LWG 3498.

diff --git a/libstdc++-v3/include/std/syncstream b/libstdc++-v3/include/std/syncstream
index 299941f..db6ebd5 100644 (file)
--- a/libstdc++-v3/include/std/syncstream
+++ b/libstdc++-v3/include/std/syncstream
@@ -114,7 +114,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       }
 
       void
-      swap(basic_syncbuf& __other) noexcept
+      swap(basic_syncbuf& __other)
       {
        using _ATr = allocator_traits<_Alloc>;
        if constexpr (!_ATr::propagate_on_container_swap::value)