qcore_unix_p.h: fix unqualified names [1/N]: SteadyClockClockId

The name is in the global namespace and lacks a Q prefix, so might
clash with names in other projects.

Fix by prepending Q.

Amends 5642b99.

There's a ton more where this came from, more than I care to fix on
the spot, so created QTBUG-144825 and QTBUG-144823 to keep track of
them.

Pick-to: 6.10
Task-number: QTBUG-144825
Change-Id: I3383380da7c40af80be2a1a469a1fa5470d8f57f
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit cdec70e)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

Author: marcmutz

src/corelib/kernel/qcore_unix_p.h

@@ -66,7 +66,7 @@ QT_BEGIN_NAMESPACE
 
 Q_DECLARE_TYPEINFO(pollfd, Q_PRIMITIVE_TYPE);
 
-static inline constexpr clockid_t SteadyClockClockId =
+static inline constexpr clockid_t QSteadyClockClockId =
 #if !defined(CLOCK_MONOTONIC)
         // we don't know how to set the monotonic clock
         CLOCK_REALTIME
@@ -100,7 +100,7 @@ static inline constexpr clockid_t QWaitConditionClockId =
         // unknown why use of the monotonic clock causes failures
         CLOCK_REALTIME
 #else
-        SteadyClockClockId;
+        QSteadyClockClockId;
 #endif
         ;
 
@@ -219,7 +219,7 @@ inline timespec qAbsTimespec(timespec ts)
     return normalizedTimespec(ts);
 }
 
-template <clockid_t ClockId = SteadyClockClockId>
+template <clockid_t ClockId = QSteadyClockClockId>
 inline timespec deadlineToAbstime(QDeadlineTimer deadline)
 {
     using namespace std::chrono;

src/corelib/thread/qthread_unix.cpp

@@ -974,7 +974,7 @@ bool QThreadPrivate::wait(QMutexLocker<QMutex> &locker, QDeadlineTimer deadline)
         pthread_cleanup_push(&CancelState::run, &nocancel);
         pthread_t thrId = from_HANDLE<pthread_t>(data->threadId.loadRelaxed());
         if constexpr (QT_CONFIG(pthread_clockjoin))
-            r = pthread_clockjoin_np(thrId, nullptr, SteadyClockClockId, pts);
+            r = pthread_clockjoin_np(thrId, nullptr, QSteadyClockClockId, pts);
         else
             r = pthread_timedjoin_np(thrId, nullptr, pts);
         Q_ASSERT(r == 0 || r == ETIMEDOUT);