New Defects reported by Coverity Scan for LibreOffice

[Caolán McNamara]

On Thu, 2023-09-28 at 06:48 +0000, scan-admin at coverity.com wrote:
> 492 new defect(s) introduced to LibreOffice found with Coverity Scan.

For the new C++ 20 baseline I bumped the compiler I used for this
build, and also bumped the coverity version I build with. I think the
new compiler brings a bunch of annoying noise in those system headers
and the new coverity is very keen on std::move. But at least some of
those std::move looks plain wrong like suggesting a std::move on return
of a static uno::Reference.

I might try and see if we can continue to use the earlier version of
coverity with the newer compiler.