Re: pkg/59028: qt5-qtwebkit doesn't build

[Taylor R Campbell <riastradh%NetBSD.org@localhost>]

> /scratch/x11/qt5-qtwebkit/work/.cwrapper/bin/c++ [...] -std=c++11 [...]
> [...]
> /usr/pkg/include/unicode/uset.h:1655:10: error: 'u16string_view' in namespace 'std' does not name a type; did you mean 'u16string'?
>  1655 |     std::u16string_view operator*() const {
>       |          ^~~~~~~~~~~~~~
>       |          u16string

This looks like C++17 <string_view> artefacts.  -std=c++11 probably
won't cut it here.  textproc/icu/buildlink3.mk probably needs to
require all downstream packages to use C++17.