qarraydata.h: use __has_builtin directly

All our supported compilers support __has_builtin; also, no need to
check for old GCC versions; we require at least GCC 8.

Change-Id: I86d955188e71d6da5ebd1b2455e0f7fad8072bfb
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/tools/qarraydata.h

@@ -139,7 +139,7 @@ struct QTypedArrayData
         static_assert(sizeof(QTypedArrayData) == sizeof(QArrayData));
         QArrayData *d;
         void *result = QArrayData::allocate(&d, sizeof(T), alignof(AlignmentDummy), capacity, option);
-#if (defined(Q_CC_GNU) && Q_CC_GNU >= 407) || QT_HAS_BUILTIN(__builtin_assume_aligned)
+#if __has_builtin(__builtin_assume_aligned)
         result = __builtin_assume_aligned(result, Q_ALIGNOF(AlignmentDummy));
 #endif
         return qMakePair(static_cast<QTypedArrayData *>(d), static_cast<T *>(result));