qt.cfg: Add support for macros Q_LIKELY and Q_UNLIKELY

Reference:
https://doc.qt.io/qt-5/qtglobal.html#Q_LIKELY
https://doc.qt.io/qt-5/qtglobal.html#Q_UNLIKELY

cfg/qt.cfg

@@ -1318,11 +1318,13 @@
   <define name="Q_FLAGS(X)" value=""/>
   <define name="Q_FOREVER" value="for (;;)"/>
   <define name="Q_INTERFACES(X)" value=""/>
+  <define name="Q_LIKELY(expr)" value="expr"/>
   <define name="Q_NULLPTR" value="NULL"/>
   <define name="Q_OBJECT" value=""/>
   <define name="Q_PROPERTY(X)" value=""/>
   <define name="Q_Q(Class)" value="Class * const q = q_func()"/>
   <define name="Q_RETURN_ARG(type, data)" value="QReturnArgument&lt;type &gt;(#type, data)"/>
+  <define name="Q_UNLIKELY(expr)" value="expr"/>
   <define name="Q_UNUSED(X)" value="(void)X;"/>
   <define name="QCOMPARE(a,b)" value="assert( (a) == (b) )"/>
   <define name="QVERIFY(expr)" value="assert( expr )"/>

test/cfg/qt.cpp

@@ -54,6 +54,9 @@ void validCode(int * pIntPtr)
         Q_FOREVER {
         }
     }
+
+    if (Q_LIKELY(pIntPtr)) {}
+    if (Q_UNLIKELY(!pIntPtr)) {}
 }
 
 void ignoredReturnValue()