Direct2D QPA plugin does not compile with Clang-cl due to overzealous constexpr

In file included from .\qwindowsdirect2dpaintengine.cpp:44:
./qwindowsdirect2dhelpers.h(53,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_RECT_U to_d2d_rect_u(const QRect &qrect)
                                    ^
./qwindowsdirect2dhelpers.h(55,12) :  note: non-constexpr function 'RectU' cannot be used in a constant expression
    return D2D1::RectU(qrect.x(), qrect.y(), qrect.x() + qrect.width(), qrect.y() + qrect.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(173,5) :  note: declared here
    RectU(
    ^
In file included from .\qwindowsdirect2dpaintengine.cpp:44:
./qwindowsdirect2dhelpers.h(58,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_RECT_F to_d2d_rect_f(const QRectF &qrect)
                                    ^
./qwindowsdirect2dhelpers.h(60,12) :  note: non-constexpr function 'RectF' cannot be used in a constant expression
    return D2D1::RectF(qrect.x(), qrect.y(), qrect.x() + qrect.width(), qrect.y() + qrect.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(160,5) :  note: declared here
    RectF(
    ^
In file included from .\qwindowsdirect2dpaintengine.cpp:44:
./qwindowsdirect2dhelpers.h(63,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_SIZE_U to_d2d_size_u(const QSizeF &qsize)
                                    ^
./qwindowsdirect2dhelpers.h(65,12) :  note: non-constexpr function 'SizeU' cannot be used in a constant expression
    return D2D1::SizeU(qsize.width(), qsize.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(133,5) :  note: declared here
    SizeU(
    ^
In file included from .\qwindowsdirect2dpaintengine.cpp:44:
./qwindowsdirect2dhelpers.h(68,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_SIZE_U to_d2d_size_u(const QSize &qsize)
                                    ^
./qwindowsdirect2dhelpers.h(70,12) :  note: non-constexpr function 'SizeU' cannot be used in a constant expression
    return D2D1::SizeU(qsize.width(), qsize.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(133,5) :  note: declared here
    SizeU(
    ^
In file included from .\qwindowsdirect2dpaintengine.cpp:44:
./qwindowsdirect2dhelpers.h(73,39) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_POINT_2F to_d2d_point_2f(const QPointF &qpoint)
                                      ^
./qwindowsdirect2dhelpers.h(75,12) :  note: non-constexpr function 'Point2F' cannot be used in a constant expression
    return D2D1::Point2F(qpoint.x(), qpoint.y());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(86,5) :  note: declared here
    Point2F(
    ^
In file included from .\qwindowsdirect2dpaintengine.cpp:44:
./qwindowsdirect2dhelpers.h(78,38) :  error: constexpr function's return type 'D2D1::ColorF' is not a literal type
Q_DECL_CONSTEXPR inline D2D1::ColorF to_d2d_color_f(const QColor &c)
                                     ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(517,11) :  note: 'ColorF' is not literal because it is not an aggregate and has no constexpr constructors other than copy or move constructors
    class ColorF : public D2D1_COLOR_F
          ^
In file included from .\qwindowsdirect2dpaintengine.cpp:44:
./qwindowsdirect2dhelpers.h(83,43) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_MATRIX_3X2_F to_d2d_matrix_3x2_f(const QTransform &transform)
                                          ^
./qwindowsdirect2dhelpers.h(85,12) :  note: non-literal type 'D2D1::Matrix3x2F' cannot be used in a constant expression
    return D2D1::Matrix3x2F(transform.m11(), transform.m12(),
           ^
7 errors generated.
In file included from .\qwindowsdirect2dpaintdevice.cpp:43:
./qwindowsdirect2dhelpers.h(53,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_RECT_U to_d2d_rect_u(const QRect &qrect)
                                    ^
./qwindowsdirect2dhelpers.h(55,12) :  note: non-constexpr function 'RectU' cannot be used in a constant expression
    return D2D1::RectU(qrect.x(), qrect.y(), qrect.x() + qrect.width(), qrect.y() + qrect.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(173,5) :  note: declared here
    RectU(
    ^
In file included from .\qwindowsdirect2dpaintdevice.cpp:43:
./qwindowsdirect2dhelpers.h(58,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_RECT_F to_d2d_rect_f(const QRectF &qrect)
                                    ^
./qwindowsdirect2dhelpers.h(60,12) :  note: non-constexpr function 'RectF' cannot be used in a constant expression
    return D2D1::RectF(qrect.x(), qrect.y(), qrect.x() + qrect.width(), qrect.y() + qrect.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(160,5) :  note: declared here
    RectF(
    ^
In file included from .\qwindowsdirect2dpaintdevice.cpp:43:
./qwindowsdirect2dhelpers.h(63,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_SIZE_U to_d2d_size_u(const QSizeF &qsize)
                                    ^
./qwindowsdirect2dhelpers.h(65,12) :  note: non-constexpr function 'SizeU' cannot be used in a constant expression
    return D2D1::SizeU(qsize.width(), qsize.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(133,5) :  note: declared here
    SizeU(
    ^
In file included from .\qwindowsdirect2dpaintdevice.cpp:43:
./qwindowsdirect2dhelpers.h(68,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_SIZE_U to_d2d_size_u(const QSize &qsize)
                                    ^
./qwindowsdirect2dhelpers.h(70,12) :  note: non-constexpr function 'SizeU' cannot be used in a constant expression
    return D2D1::SizeU(qsize.width(), qsize.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(133,5) :  note: declared here
    SizeU(
    ^
In file included from .\qwindowsdirect2dpaintdevice.cpp:43:
./qwindowsdirect2dhelpers.h(73,39) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_POINT_2F to_d2d_point_2f(const QPointF &qpoint)
                                      ^
./qwindowsdirect2dhelpers.h(75,12) :  note: non-constexpr function 'Point2F' cannot be used in a constant expression
    return D2D1::Point2F(qpoint.x(), qpoint.y());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(86,5) :  note: declared here
    Point2F(
    ^
In file included from .\qwindowsdirect2dpaintdevice.cpp:43:
./qwindowsdirect2dhelpers.h(78,38) :  error: constexpr function's return type 'D2D1::ColorF' is not a literal type
Q_DECL_CONSTEXPR inline D2D1::ColorF to_d2d_color_f(const QColor &c)
                                     ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(517,11) :  note: 'ColorF' is not literal because it is not an aggregate and has no constexpr constructors other than copy or move constructors
    class ColorF : public D2D1_COLOR_F
          ^
In file included from .\qwindowsdirect2dpaintdevice.cpp:43:
./qwindowsdirect2dhelpers.h(83,43) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_MATRIX_3X2_F to_d2d_matrix_3x2_f(const QTransform &transform)
                                          ^
./qwindowsdirect2dhelpers.h(85,12) :  note: non-literal type 'D2D1::Matrix3x2F' cannot be used in a constant expression
    return D2D1::Matrix3x2F(transform.m11(), transform.m12(),
           ^
7 errors generated.
In file included from .\qwindowsdirect2dplatformpixmap.cpp:44:
./qwindowsdirect2dhelpers.h(53,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_RECT_U to_d2d_rect_u(const QRect &qrect)
                                    ^
./qwindowsdirect2dhelpers.h(55,12) :  note: non-constexpr function 'RectU' cannot be used in a constant expression
    return D2D1::RectU(qrect.x(), qrect.y(), qrect.x() + qrect.width(), qrect.y() + qrect.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(173,5) :  note: declared here
    RectU(
    ^
In file included from .\qwindowsdirect2dplatformpixmap.cpp:44:
./qwindowsdirect2dhelpers.h(58,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_RECT_F to_d2d_rect_f(const QRectF &qrect)
                                    ^
./qwindowsdirect2dhelpers.h(60,12) :  note: non-constexpr function 'RectF' cannot be used in a constant expression
    return D2D1::RectF(qrect.x(), qrect.y(), qrect.x() + qrect.width(), qrect.y() + qrect.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(160,5) :  note: declared here
    RectF(
    ^
In file included from .\qwindowsdirect2dplatformpixmap.cpp:44:
./qwindowsdirect2dhelpers.h(63,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_SIZE_U to_d2d_size_u(const QSizeF &qsize)
                                    ^
./qwindowsdirect2dhelpers.h(65,12) :  note: non-constexpr function 'SizeU' cannot be used in a constant expression
    return D2D1::SizeU(qsize.width(), qsize.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(133,5) :  note: declared here
    SizeU(
    ^
In file included from .\qwindowsdirect2dplatformpixmap.cpp:44:
./qwindowsdirect2dhelpers.h(68,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_SIZE_U to_d2d_size_u(const QSize &qsize)
                                    ^
./qwindowsdirect2dhelpers.h(70,12) :  note: non-constexpr function 'SizeU' cannot be used in a constant expression
    return D2D1::SizeU(qsize.width(), qsize.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(133,5) :  note: declared here
    SizeU(
    ^
In file included from .\qwindowsdirect2dplatformpixmap.cpp:44:
./qwindowsdirect2dhelpers.h(73,39) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_POINT_2F to_d2d_point_2f(const QPointF &qpoint)
                                      ^
./qwindowsdirect2dhelpers.h(75,12) :  note: non-constexpr function 'Point2F' cannot be used in a constant expression
    return D2D1::Point2F(qpoint.x(), qpoint.y());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(86,5) :  note: declared here
    Point2F(
    ^
In file included from .\qwindowsdirect2dplatformpixmap.cpp:44:
./qwindowsdirect2dhelpers.h(78,38) :  error: constexpr function's return type 'D2D1::ColorF' is not a literal type
Q_DECL_CONSTEXPR inline D2D1::ColorF to_d2d_color_f(const QColor &c)
                                     ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(517,11) :  note: 'ColorF' is not literal because it is not an aggregate and has no constexpr constructors other than copy or move constructors
    class ColorF : public D2D1_COLOR_F
          ^
In file included from .\qwindowsdirect2dplatformpixmap.cpp:44:
./qwindowsdirect2dhelpers.h(83,43) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_MATRIX_3X2_F to_d2d_matrix_3x2_f(const QTransform &transform)
                                          ^
./qwindowsdirect2dhelpers.h(85,12) :  note: non-literal type 'D2D1::Matrix3x2F' cannot be used in a constant expression
    return D2D1::Matrix3x2F(transform.m11(), transform.m12(),
           ^
7 errors generated.
In file included from .\qwindowsdirect2dcontext.cpp:41:
./qwindowsdirect2dhelpers.h(53,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_RECT_U to_d2d_rect_u(const QRect &qrect)
                                    ^
./qwindowsdirect2dhelpers.h(55,12) :  note: non-constexpr function 'RectU' cannot be used in a constant expression
    return D2D1::RectU(qrect.x(), qrect.y(), qrect.x() + qrect.width(), qrect.y() + qrect.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(173,5) :  note: declared here
    RectU(
    ^
In file included from .\qwindowsdirect2dcontext.cpp:41:
./qwindowsdirect2dhelpers.h(58,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_RECT_F to_d2d_rect_f(const QRectF &qrect)
                                    ^
./qwindowsdirect2dhelpers.h(60,12) :  note: non-constexpr function 'RectF' cannot be used in a constant expression
    return D2D1::RectF(qrect.x(), qrect.y(), qrect.x() + qrect.width(), qrect.y() + qrect.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(160,5) :  note: declared here
    RectF(
    ^
In file included from .\qwindowsdirect2dcontext.cpp:41:
./qwindowsdirect2dhelpers.h(63,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_SIZE_U to_d2d_size_u(const QSizeF &qsize)
                                    ^
./qwindowsdirect2dhelpers.h(65,12) :  note: non-constexpr function 'SizeU' cannot be used in a constant expression
    return D2D1::SizeU(qsize.width(), qsize.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(133,5) :  note: declared here
    SizeU(
    ^
In file included from .\qwindowsdirect2dcontext.cpp:41:
./qwindowsdirect2dhelpers.h(68,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_SIZE_U to_d2d_size_u(const QSize &qsize)
                                    ^
./qwindowsdirect2dhelpers.h(70,12) :  note: non-constexpr function 'SizeU' cannot be used in a constant expression
    return D2D1::SizeU(qsize.width(), qsize.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(133,5) :  note: declared here
    SizeU(
    ^
In file included from .\qwindowsdirect2dcontext.cpp:41:
./qwindowsdirect2dhelpers.h(73,39) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_POINT_2F to_d2d_point_2f(const QPointF &qpoint)
                                      ^
./qwindowsdirect2dhelpers.h(75,12) :  note: non-constexpr function 'Point2F' cannot be used in a constant expression
    return D2D1::Point2F(qpoint.x(), qpoint.y());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(86,5) :  note: declared here
    Point2F(
    ^
In file included from .\qwindowsdirect2dcontext.cpp:41:
./qwindowsdirect2dhelpers.h(78,38) :  error: constexpr function's return type 'D2D1::ColorF' is not a literal type
Q_DECL_CONSTEXPR inline D2D1::ColorF to_d2d_color_f(const QColor &c)
                                     ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(517,11) :  note: 'ColorF' is not literal because it is not an aggregate and has no constexpr constructors other than copy or move constructors
    class ColorF : public D2D1_COLOR_F
          ^
In file included from .\qwindowsdirect2dcontext.cpp:41:
./qwindowsdirect2dhelpers.h(83,43) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_MATRIX_3X2_F to_d2d_matrix_3x2_f(const QTransform &transform)
                                          ^
./qwindowsdirect2dhelpers.h(85,12) :  note: non-literal type 'D2D1::Matrix3x2F' cannot be used in a constant expression
    return D2D1::Matrix3x2F(transform.m11(), transform.m12(),
           ^
7 errors generated.
In file included from .\qwindowsdirect2dbitmap.cpp:42:
./qwindowsdirect2dhelpers.h(53,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_RECT_U to_d2d_rect_u(const QRect &qrect)
                                    ^
./qwindowsdirect2dhelpers.h(55,12) :  note: non-constexpr function 'RectU' cannot be used in a constant expression
    return D2D1::RectU(qrect.x(), qrect.y(), qrect.x() + qrect.width(), qrect.y() + qrect.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(173,5) :  note: declared here
    RectU(
    ^
In file included from .\qwindowsdirect2dbitmap.cpp:42:
./qwindowsdirect2dhelpers.h(58,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_RECT_F to_d2d_rect_f(const QRectF &qrect)
                                    ^
./qwindowsdirect2dhelpers.h(60,12) :  note: non-constexpr function 'RectF' cannot be used in a constant expression
    return D2D1::RectF(qrect.x(), qrect.y(), qrect.x() + qrect.width(), qrect.y() + qrect.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(160,5) :  note: declared here
    RectF(
    ^
In file included from .\qwindowsdirect2dbitmap.cpp:42:
./qwindowsdirect2dhelpers.h(63,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_SIZE_U to_d2d_size_u(const QSizeF &qsize)
                                    ^
./qwindowsdirect2dhelpers.h(65,12) :  note: non-constexpr function 'SizeU' cannot be used in a constant expression
    return D2D1::SizeU(qsize.width(), qsize.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(133,5) :  note: declared here
    SizeU(
    ^
In file included from .\qwindowsdirect2dbitmap.cpp:42:
./qwindowsdirect2dhelpers.h(68,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_SIZE_U to_d2d_size_u(const QSize &qsize)
                                    ^
./qwindowsdirect2dhelpers.h(70,12) :  note: non-constexpr function 'SizeU' cannot be used in a constant expression
    return D2D1::SizeU(qsize.width(), qsize.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(133,5) :  note: declared here
    SizeU(
    ^
In file included from .\qwindowsdirect2dbitmap.cpp:42:
./qwindowsdirect2dhelpers.h(73,39) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_POINT_2F to_d2d_point_2f(const QPointF &qpoint)
                                      ^
./qwindowsdirect2dhelpers.h(75,12) :  note: non-constexpr function 'Point2F' cannot be used in a constant expression
    return D2D1::Point2F(qpoint.x(), qpoint.y());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(86,5) :  note: declared here
    Point2F(
    ^
In file included from .\qwindowsdirect2dbitmap.cpp:42:
./qwindowsdirect2dhelpers.h(78,38) :  error: constexpr function's return type 'D2D1::ColorF' is not a literal type
Q_DECL_CONSTEXPR inline D2D1::ColorF to_d2d_color_f(const QColor &c)
                                     ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(517,11) :  note: 'ColorF' is not literal because it is not an aggregate and has no constexpr constructors other than copy or move constructors
    class ColorF : public D2D1_COLOR_F
          ^
In file included from .\qwindowsdirect2dbitmap.cpp:42:
./qwindowsdirect2dhelpers.h(83,43) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_MATRIX_3X2_F to_d2d_matrix_3x2_f(const QTransform &transform)
                                          ^
./qwindowsdirect2dhelpers.h(85,12) :  note: non-literal type 'D2D1::Matrix3x2F' cannot be used in a constant expression
    return D2D1::Matrix3x2F(transform.m11(), transform.m12(),
           ^
.\qwindowsdirect2dbitmap.cpp(58,11) :  warning: field 'bitmap' will be initialized after field 'deviceContext' [-Wreorder]
        : bitmap(bm)
          ^
1 warning and 7 errors generated.
In file included from .\qwindowsdirect2ddevicecontext.cpp:41:
./qwindowsdirect2dhelpers.h(53,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_RECT_U to_d2d_rect_u(const QRect &qrect)
                                    ^
./qwindowsdirect2dhelpers.h(55,12) :  note: non-constexpr function 'RectU' cannot be used in a constant expression
    return D2D1::RectU(qrect.x(), qrect.y(), qrect.x() + qrect.width(), qrect.y() + qrect.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(173,5) :  note: declared here
    RectU(
    ^
In file included from .\qwindowsdirect2ddevicecontext.cpp:41:
./qwindowsdirect2dhelpers.h(58,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_RECT_F to_d2d_rect_f(const QRectF &qrect)
                                    ^
./qwindowsdirect2dhelpers.h(60,12) :  note: non-constexpr function 'RectF' cannot be used in a constant expression
    return D2D1::RectF(qrect.x(), qrect.y(), qrect.x() + qrect.width(), qrect.y() + qrect.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(160,5) :  note: declared here
    RectF(
    ^
In file included from .\qwindowsdirect2ddevicecontext.cpp:41:
./qwindowsdirect2dhelpers.h(63,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_SIZE_U to_d2d_size_u(const QSizeF &qsize)
                                    ^
./qwindowsdirect2dhelpers.h(65,12) :  note: non-constexpr function 'SizeU' cannot be used in a constant expression
    return D2D1::SizeU(qsize.width(), qsize.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(133,5) :  note: declared here
    SizeU(
    ^
In file included from .\qwindowsdirect2ddevicecontext.cpp:41:
./qwindowsdirect2dhelpers.h(68,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_SIZE_U to_d2d_size_u(const QSize &qsize)
                                    ^
./qwindowsdirect2dhelpers.h(70,12) :  note: non-constexpr function 'SizeU' cannot be used in a constant expression
    return D2D1::SizeU(qsize.width(), qsize.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(133,5) :  note: declared here
    SizeU(
    ^
In file included from .\qwindowsdirect2ddevicecontext.cpp:41:
./qwindowsdirect2dhelpers.h(73,39) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_POINT_2F to_d2d_point_2f(const QPointF &qpoint)
                                      ^
./qwindowsdirect2dhelpers.h(75,12) :  note: non-constexpr function 'Point2F' cannot be used in a constant expression
    return D2D1::Point2F(qpoint.x(), qpoint.y());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(86,5) :  note: declared here
    Point2F(
    ^
In file included from .\qwindowsdirect2ddevicecontext.cpp:41:
./qwindowsdirect2dhelpers.h(78,38) :  error: constexpr function's return type 'D2D1::ColorF' is not a literal type
Q_DECL_CONSTEXPR inline D2D1::ColorF to_d2d_color_f(const QColor &c)
                                     ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(517,11) :  note: 'ColorF' is not literal because it is not an aggregate and has no constexpr constructors other than copy or move constructors
    class ColorF : public D2D1_COLOR_F
          ^
In file included from .\qwindowsdirect2ddevicecontext.cpp:41:
./qwindowsdirect2dhelpers.h(83,43) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_MATRIX_3X2_F to_d2d_matrix_3x2_f(const QTransform &transform)
                                          ^
./qwindowsdirect2dhelpers.h(85,12) :  note: non-literal type 'D2D1::Matrix3x2F' cannot be used in a constant expression
    return D2D1::Matrix3x2F(transform.m11(), transform.m12(),
           ^
7 errors generated.
In file included from .\qwindowsdirect2dwindow.cpp:44:
./qwindowsdirect2dhelpers.h(53,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_RECT_U to_d2d_rect_u(const QRect &qrect)
                                    ^
./qwindowsdirect2dhelpers.h(55,12) :  note: non-constexpr function 'RectU' cannot be used in a constant expression
    return D2D1::RectU(qrect.x(), qrect.y(), qrect.x() + qrect.width(), qrect.y() + qrect.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(173,5) :  note: declared here
    RectU(
    ^
In file included from .\qwindowsdirect2dwindow.cpp:44:
./qwindowsdirect2dhelpers.h(58,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_RECT_F to_d2d_rect_f(const QRectF &qrect)
                                    ^
./qwindowsdirect2dhelpers.h(60,12) :  note: non-constexpr function 'RectF' cannot be used in a constant expression
    return D2D1::RectF(qrect.x(), qrect.y(), qrect.x() + qrect.width(), qrect.y() + qrect.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(160,5) :  note: declared here
    RectF(
    ^
In file included from .\qwindowsdirect2dwindow.cpp:44:
./qwindowsdirect2dhelpers.h(63,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_SIZE_U to_d2d_size_u(const QSizeF &qsize)
                                    ^
./qwindowsdirect2dhelpers.h(65,12) :  note: non-constexpr function 'SizeU' cannot be used in a constant expression
    return D2D1::SizeU(qsize.width(), qsize.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(133,5) :  note: declared here
    SizeU(
    ^
In file included from .\qwindowsdirect2dwindow.cpp:44:
./qwindowsdirect2dhelpers.h(68,37) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_SIZE_U to_d2d_size_u(const QSize &qsize)
                                    ^
./qwindowsdirect2dhelpers.h(70,12) :  note: non-constexpr function 'SizeU' cannot be used in a constant expression
    return D2D1::SizeU(qsize.width(), qsize.height());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(133,5) :  note: declared here
    SizeU(
    ^
In file included from .\qwindowsdirect2dwindow.cpp:44:
./qwindowsdirect2dhelpers.h(73,39) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_POINT_2F to_d2d_point_2f(const QPointF &qpoint)
                                      ^
./qwindowsdirect2dhelpers.h(75,12) :  note: non-constexpr function 'Point2F' cannot be used in a constant expression
    return D2D1::Point2F(qpoint.x(), qpoint.y());
           ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(86,5) :  note: declared here
    Point2F(
    ^
In file included from .\qwindowsdirect2dwindow.cpp:44:
./qwindowsdirect2dhelpers.h(78,38) :  error: constexpr function's return type 'D2D1::ColorF' is not a literal type
Q_DECL_CONSTEXPR inline D2D1::ColorF to_d2d_color_f(const QColor &c)
                                     ^
C:\Program Files (x86)\Windows Kits\10\include\10.0.10586.0\um\d2d1helper.h(517,11) :  note: 'ColorF' is not literal because it is not an aggregate and has no constexpr constructors other than copy or move constructors
    class ColorF : public D2D1_COLOR_F
          ^
In file included from .\qwindowsdirect2dwindow.cpp:44:
./qwindowsdirect2dhelpers.h(83,43) :  error: constexpr function never produces a constant expression [-Winvalid-constexpr]
Q_DECL_CONSTEXPR inline D2D1_MATRIX_3X2_F to_d2d_matrix_3x2_f(const QTransform &transform)
                                          ^
./qwindowsdirect2dhelpers.h(85,12) :  note: non-literal type 'D2D1::Matrix3x2F' cannot be used in a constant expression
    return D2D1::Matrix3x2F(transform.m11(), transform.m12(),
           ^
7 errors generated.
NMAKE : fatal error U1077: 'D:\opt\LLVM64_390\bin\clang-cl.EXE' : return code '0x1'