Don't wrap feature detection macros with QT_HAS_FOO() variants

Using wrappers for these macros is problematic when for example passing the
-frewrite-includes flag to preprocess sources before shipping off to distcc
or Icecream. It will also start producing warnings when compilers implement
http://eel.is/c++draft/cpp.cond#7.sentence-2. See for example
https://reviews.llvm.org/D49091

Both https://clang.llvm.org/docs/LanguageExtensions.html and the SD-6 document at
https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations
recommend defining '__has_foo(x) 0' as a fallback for compilers without the
macros, so that's what we go for.

Change-Id: I0298cd3b4a6ff6618821e34642a5ddd6728be767
Reviewed-by: Alex Richardson <arichardson.kde@gmail.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/src/corelib/kernel/qtimer.h b/src/corelib/kernel/qtimer.h
index eb7185c12d..6bbfd741d9 100644
--- a/src/corelib/kernel/qtimer.h
+++ b/src/corelib/kernel/qtimer.h
@@ -47,7 +47,7 @@
 #include <QtCore/qbasictimer.h> // conceptual inheritance
 #include <QtCore/qobject.h>
 
-#if QT_HAS_INCLUDE(<chrono>)
+#if __has_include(<chrono>)
 #  include <chrono>
 #endif
 
@@ -177,7 +177,7 @@ Q_SIGNALS:
     void timeout(QPrivateSignal);
 
 public:
-#if QT_HAS_INCLUDE(<chrono>) || defined(Q_QDOC)
+#if __has_include(<chrono>) || defined(Q_QDOC)
     void setInterval(std::chrono::milliseconds value)
     {
         setInterval(int(value.count()));
@@ -223,7 +223,7 @@ private:
     static void singleShotImpl(int msec, Qt::TimerType timerType,
                                const QObject *receiver, QtPrivate::QSlotObjectBase *slotObj);
 
-#if QT_HAS_INCLUDE(<chrono>)
+#if __has_include(<chrono>)
     static Qt::TimerType defaultTypeFor(std::chrono::milliseconds interval)
     { return defaultTypeFor(int(interval.count())); }