libstdc++: Remove unnecessary uses of <utility>

The <algorithm> header includes <utility>, with a comment referring to
UK-300, a National Body comment on the C++11 draft. That comment
proposed to move std::swap to <utility> and then require <algorithm> to
include <utility>. The comment was rejected, so we do not need to
implement the suggestion. For backwards compatibility with C++03 we do
want <algorithm> to define std::swap, but it does so anyway via
<bits/move.h>. We don't need the whole of <utility> to do that.

A few other headers that need std::swap can include <bits/move.h> to
get it, instead of <utility>.

There are several headers that include <utility> to get std::pair, but
they can use <bits/stl_pair.h> to get it without also including the
rel_ops namespace and other contents of <utility>.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	* include/std/algorithm: Do not include <utility>.
	* include/std/functional: Likewise.
	* include/std/regex: Include <bits/stl_pair.h> instead of
	<utility>.
	* include/debug/map.h: Likewise.
	* include/debug/multimap.h: Likewise.
	* include/debug/multiset.h: Likewise.
	* include/debug/set.h: Likewise.
	* include/debug/vector: Likewise.
	* include/bits/fs_path.h: Likewise.
	* include/bits/unique_ptr.h: Do not include <utility>.
	* include/experimental/any: Likewise.
	* include/experimental/executor: Likewise.
	* include/experimental/memory: Likewise.
	* include/experimental/optional: Likewise.
	* include/experimental/socket: Use __exchange instead
	of std::exchange.
	* src/filesystem/ops-common.h: Likewise.
	* testsuite/20_util/default_delete/48631_neg.cc: Adjust expected
	errors to not use a hardcoded line number.
	* testsuite/20_util/default_delete/void_neg.cc: Likewise.
	* testsuite/20_util/specialized_algorithms/uninitialized_copy/constrained.cc:
	Include <utility> for std::as_const.
	* testsuite/20_util/specialized_algorithms/uninitialized_default_construct/constrained.cc:
	Likewise.
	* testsuite/20_util/specialized_algorithms/uninitialized_move/constrained.cc:
	Likewise.
	* testsuite/20_util/specialized_algorithms/uninitialized_value_construct/constrained.cc:
	Likewise.
	* testsuite/23_containers/vector/cons/destructible_debug_neg.cc:
	Adjust dg-error line number.

5 files changed, 7 insertions, 9 deletions

diff --git a/libstdc++-v3/include/experimental/any b/libstdc++-v3/include/experimental/any
index 3bb3e8c4a0a..7d18f267e8b 100644
--- a/libstdc++-v3/include/experimental/any
+++ b/libstdc++-v3/include/experimental/any
@@ -36,8 +36,8 @@
 
 #include <typeinfo>
 #include <new>
-#include <utility>
 #include <type_traits>
+#include <bits/move.h>
 #include <experimental/bits/lfts_config.h>
 
 namespace std _GLIBCXX_VISIBILITY(default)
diff --git a/libstdc++-v3/include/experimental/executor b/libstdc++-v3/include/experimental/executor
index c670f2739b6..4322a7f5caf 100644
--- a/libstdc++-v3/include/experimental/executor
+++ b/libstdc++-v3/include/experimental/executor
@@ -43,7 +43,6 @@
 #include <thread>
 #include <tuple>
 #include <unordered_map>
-#include <utility>
 #include <experimental/netfwd>
 #include <bits/unique_ptr.h>
 #include <experimental/bits/net.h>
diff --git a/libstdc++-v3/include/experimental/memory b/libstdc++-v3/include/experimental/memory
index a74b2402f7a..a89a5ecfa84 100644
--- a/libstdc++-v3/include/experimental/memory
+++ b/libstdc++-v3/include/experimental/memory
@@ -40,7 +40,6 @@
 
 #include <memory>
 #include <type_traits>
-#include <utility>
 #include <experimental/bits/shared_ptr.h>
 #include <bits/functional_hash.h>
 
diff --git a/libstdc++-v3/include/experimental/optional b/libstdc++-v3/include/experimental/optional
index ae2418f0500..431d23631cf 100644
--- a/libstdc++-v3/include/experimental/optional
+++ b/libstdc++-v3/include/experimental/optional
@@ -32,7 +32,6 @@
 
 #if __cplusplus >= 201402L
 
-#include <utility>
 #include <type_traits>
 #include <stdexcept>
 #include <new>
@@ -40,6 +39,7 @@
 #include <bits/functexcept.h>
 #include <bits/functional_hash.h>
 #include <bits/enable_special_members.h>
+#include <bits/move.h>
 #include <experimental/bits/lfts_config.h>
 
 namespace std _GLIBCXX_VISIBILITY(default)
diff --git a/libstdc++-v3/include/experimental/socket b/libstdc++-v3/include/experimental/socket
index 9db4a245ccf..6d1c114254a 100644
--- a/libstdc++-v3/include/experimental/socket
+++ b/libstdc++-v3/include/experimental/socket
@@ -429,16 +429,16 @@ inline namespace v1
 
     __socket_impl(__socket_impl&& __rhs)
     : _M_ctx(__rhs._M_ctx),
-      _M_sockfd(std::exchange(__rhs._M_sockfd, -1)),
-      _M_bits(std::exchange(__rhs._M_bits, {}))
+      _M_sockfd(std::__exchange(__rhs._M_sockfd, -1)),
+      _M_bits(std::__exchange(__rhs._M_bits, {}))
     { }
 
     __socket_impl&
     operator=(__socket_impl&& __rhs)
     {
       _M_ctx = __rhs._M_ctx;
-      _M_sockfd = std::exchange(__rhs._M_sockfd, -1);
-      _M_bits = std::exchange(__rhs._M_bits, {});
+      _M_sockfd = std::__exchange(__rhs._M_sockfd, -1);
+      _M_bits = std::__exchange(__rhs._M_bits, {});
       return *this;
     }
 
@@ -615,7 +615,7 @@ inline namespace v1
       {
 	__glibcxx_assert(is_open());
 	cancel(__ec);
-	return std::exchange(_M_sockfd, -1);
+	return std::__exchange(_M_sockfd, -1);
       }
 
       template<typename _SettableSocketOption>