Don't enable the requires clause for some Xcode Clang

...even when building with -std=c++20 (cf.
<https://gerrit.libreoffice.org/c/core/+/155121> "Bump baseline to C++20"), as
that causes

> In file included from animations/source/animcore/animcore.cxx:20:
> In file included from workdir/UnoApiHeadersTarget/offapi/normal/com/sun/star/util/XCloneable.hpp:8:
> workdir/UnoApiHeadersTarget/udkapi/normal/com/sun/star/uno/XInterface.hpp:32:65: error: invalid application of 'sizeof' to an incomplete type 'animcore::(anonymous namespace)::AnimationNode'
> template<typename T> inline constexpr auto isUnoInterfaceType = sizeof (T) && IsUnoInterfaceType<T>::value;
>                                                                 ^~~~~~~~~~
> include/unotools/weakref.hxx:119:33: note: in instantiation of variable template specialization 'cppu::detail::isUnoInterfaceType' requested here
>         requires(!cppu::detail::isUnoInterfaceType<interface_type>)
>                                 ^
> animations/source/animcore/animcore.cxx:310:44: note: in instantiation of template class 'unotools::WeakReference<animcore::(anonymous namespace)::AnimationNode>' requested here
>     unotools::WeakReference<AnimationNode> mxParent;
>                                            ^
> animations/source/animcore/animcore.cxx:122:7: note: definition of 'animcore::(anonymous namespace)::AnimationNode' is not complete until the closing '}'
> class AnimationNode final:  public AnimationNodeBase
>       ^

at least with Xcode 14.3.1.

Change-Id: Iea6690578cd328545f54254acc0099947778c03e
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/155220
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

0 files changed, 0 insertions, 0 deletions