libreoffice 6.3 fails to compile on -current

[Michael Butler]

For my test compile, failure looks like this ..

/usr/ports/editors/libreoffice/work/libreoffice-6.3.0.4/vcl/qt5/Qt5Instance.cxx:416:25:
error: no viable constructor or deduction guide for deduction of
template arguments of 'function'
        RunInMainThread(std::function([&, this]() { pPicker =
createPicker(context, eMode); }));
                        ^
/usr/include/c++/v1/functional:1427:48: note: candidate template
ignored: could not match 'function<_Fp>' against '(lambda at
/usr/ports/editors/libreoffice/work/libreoffice-6.3.0.4/vcl/qt5/Qt5Instance.cxx:416:39)'
template<class _Fp> class _LIBCPP_TEMPLATE_VIS function; // undefined
                                               ^
/usr/include/c++/v1/functional:1427:48: note: candidate function
template not viable: requires 0 arguments, but 1 was provided
1 error generated.
gmake[3]: ***
[/usr/ports/editors/libreoffice/work/libreoffice-6.3.0.4/solenv/gbuild/LinkTarget.mk:293:
/usr/ports/editors/libreoffice/work/libreoffice-6.3.0.4/workdir/CxxObject/vcl/qt5/Qt5Instance.o]
Error 1

	imb