libstdc++: Fix errors in <experimental/internet>

libstdc++-v3/ChangeLog:

	* include/experimental/internet (address_v6::any): Avoid using
	memcpy in constexpr function.
	(address_v6::loopback): Likewise.
	(make_address_v6): Fix missing return statements on error paths.
	* include/experimental/io_context: Avoid -Wdangling-else
	warning.
	* testsuite/experimental/net/internet/address/v4/members.cc:
	Remove unused variables.
	* testsuite/experimental/net/internet/address/v6/members.cc:
	New test.

2 files changed, 21 insertions, 11 deletions

diff --git a/libstdc++-v3/include/experimental/internet b/libstdc++-v3/include/experimental/internet
index 2fc2533..5783167 100644
--- a/libstdc++-v3/include/experimental/internet
+++ b/libstdc++-v3/include/experimental/internet
@@ -354,19 +354,18 @@ namespace ip
 #endif
 
     // static members:
+
     static constexpr address_v6
     any() noexcept
     {
-      address_v6 __addr;
-      __builtin_memcpy(&__addr._M_bytes, in6addr_any.s6_addr, 16);
-      return __addr;
+      return {};
     }
 
     static constexpr address_v6
     loopback() noexcept
     {
       address_v6 __addr;
-      __builtin_memcpy(&__addr._M_bytes, in6addr_loopback.s6_addr, 16);
+      __addr._M_bytes[15] = 1;
       return __addr;
     }
 
@@ -755,7 +754,10 @@ namespace ip
 	__str++;
       }
     if (__out == std::end(__buf))
-      __ec = std::make_error_code(std::errc::invalid_argument);
+      {
+	__ec = std::make_error_code(std::errc::invalid_argument);
+	return {};
+      }
     else
       {
 	*__out = '\0';
@@ -790,7 +792,10 @@ namespace ip
 	__n++;
       }
     if (__out == std::end(__buf))
-      __ec = std::make_error_code(std::errc::invalid_argument);
+      {
+	__ec = std::make_error_code(std::errc::invalid_argument);
+	return {};
+      }
     else
       {
 	*__out = '\0';
@@ -835,7 +840,10 @@ namespace ip
 	__n++;
       }
     if (__out == std::end(__buf))
-      __ec = std::make_error_code(std::errc::invalid_argument);
+      {
+	__ec = std::make_error_code(std::errc::invalid_argument);
+	return {};
+      }
     else
       {
 	*__out = '\0';
diff --git a/libstdc++-v3/include/experimental/io_context b/libstdc++-v3/include/experimental/io_context
index 12c269b..c82f30c 100644
--- a/libstdc++-v3/include/experimental/io_context
+++ b/libstdc++-v3/include/experimental/io_context
@@ -680,10 +680,12 @@ inline namespace v1
 	    continue;
 
 	  if (__res == __reactor::_S_timeout)
-	    if (__timerq == nullptr)
-	      return false;
-	    else
-	      continue;  // timed out, so restart loop and process the timer
+	    {
+	      if (__timerq == nullptr)
+		return false;
+	      else
+		continue;  // timed out, so restart loop and process the timer
+	    }
 
 	  __timerq = nullptr;