libstdc++: Guard mutex and condvar with gthreads macro [PR103638]

A mutex and condition variable is used for timed waits on atomics if
there is no "platform wait" (e.g. futex) supported. But the use of those
types wasn't guarded by the _GLIBCXX_HAS_GTHREADS macro, causing errors
for --disable-threads builds. This fix allows <atomic> to work on
targets with futexes but no gthreads.

libstdc++-v3/ChangeLog:

	PR libstdc++/103638
	* include/bits/atomic_timed_wait.h: Check _GLIBCXX_HAS_GTHREADS
	before using std::mutex and std::__condvar.

(cherry picked from commit ffb632517fc446474baba10ee2ff13a218ec2c7b)

diff --git a/libstdc++-v3/include/bits/atomic_timed_wait.h b/libstdc++-v3/include/bits/atomic_timed_wait.h
index d423a7af7c30d3790a3d0b8da512d970ceaee639..4302774958de3a42653a4a743c7c4fa8920134d1 100644 (file)
--- a/libstdc++-v3/include/bits/atomic_timed_wait.h
+++ b/libstdc++-v3/include/bits/atomic_timed_wait.h
@@ -139,6 +139,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 // (e.g. __ulock_wait())which is better than pthread_cond_clockwait
 #endif // ! PLATFORM_TIMED_WAIT
 
+#ifdef _GLIBCXX_HAS_GTHREADS
     // Returns true if wait ended before timeout.
     // _Clock must be either steady_clock or system_clock.
     template<typename _Clock, typename _Dur>
@@ -194,6 +195,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
            return false;
          }
       }
+#endif // _GLIBCXX_HAS_GTHREADS
 
     struct __timed_waiter_pool : __waiter_pool_base
     {
@@ -241,6 +243,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        if (_M_deadline <= __now)
          return false;
 
+       // FIXME: this_thread::sleep_for not available #ifdef _GLIBCXX_NO_SLEEP
+
        auto __elapsed = __now - _M_t0;
        if (__elapsed > 128ms)
          {