Short live Q_CONSTINIT!

It expands to the first available of

- constinit (C++20)
- [[clang::require_constant_initialization]] (Clang)
- __constinit (GCC >= 10)

Use it around the code (on and near static QBasicAtomic; this patch
makes no attempt to find all statics in qtbase).

[ChangeLog][QtCore][QtGlobal] Added macro Q_CONSTINIT.

Fixes: QTBUG-100484
Change-Id: I11e0363a7acb3464476859d12ec7f94319d82be7
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/corelib/kernel/qeventdispatcher_glib.cpp b/src/corelib/kernel/qeventdispatcher_glib.cpp
index 974ce7f5e1..cff3efd1cc 100644
--- a/src/corelib/kernel/qeventdispatcher_glib.cpp
+++ b/src/corelib/kernel/qeventdispatcher_glib.cpp
@@ -296,7 +296,7 @@ QEventDispatcherGlibPrivate::QEventDispatcherGlibPrivate(GMainContext *context)
 {
 #if GLIB_MAJOR_VERSION == 2 && GLIB_MINOR_VERSION < 32
     if (qEnvironmentVariableIsEmpty("QT_NO_THREADED_GLIB")) {
-        static QBasicMutex mutex;
+        Q_CONSTINIT static QBasicMutex mutex;
         QMutexLocker locker(&mutex);
         if (!g_thread_supported())
             g_thread_init(NULL);