libstdc++: Reduce headers included by <future>

The <future> header only needs std::atomic_flag, so can include
<bits/atomic_base.h> instead of the whole of <atomic>.

libstdc++-v3/ChangeLog:

	* include/std/future: Include <bits/atomic_base.h> instead of
	<atomic>.

diff --git a/libstdc++-v3/include/std/future b/libstdc++-v3/include/std/future
index 09e54c3703baa7413f132c82922cd5b99162f0fb..ace0c311f1ad46a72c5327ccf804638247c5fa6b 100644 (file)
--- a/libstdc++-v3/include/std/future
+++ b/libstdc++-v3/include/std/future
@@ -38,9 +38,10 @@
 #include <mutex>             // call_once
 #include <condition_variable> // __at_thread_exit_elt
 #include <system_error>
-#include <atomic>
+#include <bits/atomic_base.h> // atomic_flag
 #include <bits/allocated_ptr.h>
 #include <bits/atomic_futex.h>
+#include <bits/exception_defines.h>
 #include <bits/invoke.h>
 #include <bits/unique_ptr.h>
 #include <bits/shared_ptr.h>