Replace custom type traits with std one's

Remove most type traits from qtypetraits.h, but keep the custom
implementation of is_signed/is_unsigned. This gets rid of
BSD-3 licensed code from Google in a public header (hugh!).

The custom implementations for is_signed/is_unsigned are kept
because the implementations in gcc's standard headers do not
work as we expect for enums - both is_signed and is_unsigned
always returns false there - see also
  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59027

[ChangeLog][QtCore][General] Qt now relies on type traits from
the C++ standard library.

Change-Id: I3f2188b46949f04ca4482a6ac9afd3482103f0e1
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/src/corelib/kernel/qvariant_p.h b/src/corelib/kernel/qvariant_p.h
index d01f386032..ec87e20656 100644
--- a/src/corelib/kernel/qvariant_p.h
+++ b/src/corelib/kernel/qvariant_p.h
@@ -66,7 +66,7 @@ struct QVariantIntegrator
 {
     static const bool CanUseInternalSpace = sizeof(T) <= sizeof(QVariant::Private::Data)
                                             && ((QTypeInfoQuery<T>::isRelocatable) || Q_IS_ENUM(T));
-    typedef QtPrivate::integral_constant<bool, CanUseInternalSpace> CanUseInternalSpace_t;
+    typedef std::integral_constant<bool, CanUseInternalSpace> CanUseInternalSpace_t;
 };
 Q_STATIC_ASSERT(QVariantIntegrator<double>::CanUseInternalSpace);
 Q_STATIC_ASSERT(QVariantIntegrator<long int>::CanUseInternalSpace);
@@ -118,28 +118,28 @@ private:
 };
 
 template <class T>
-inline void v_construct_helper(QVariant::Private *x, const T &t, QtPrivate::true_type)
+inline void v_construct_helper(QVariant::Private *x, const T &t, std::true_type)
 {
     new (&x->data) T(t);
     x->is_shared = false;
 }
 
 template <class T>
-inline void v_construct_helper(QVariant::Private *x, const T &t, QtPrivate::false_type)
+inline void v_construct_helper(QVariant::Private *x, const T &t, std::false_type)
 {
     x->data.shared = new QVariantPrivateSharedEx<T>(t);
     x->is_shared = true;
 }
 
 template <class T>
-inline void v_construct_helper(QVariant::Private *x, QtPrivate::true_type)
+inline void v_construct_helper(QVariant::Private *x, std::true_type)
 {
     new (&x->data) T();
     x->is_shared = false;
 }
 
 template <class T>
-inline void v_construct_helper(QVariant::Private *x, QtPrivate::false_type)
+inline void v_construct_helper(QVariant::Private *x, std::false_type)
 {
     x->data.shared = new QVariantPrivateSharedEx<T>;
     x->is_shared = true;