* Makes KScreenLocker's Wayland dep optional.

user/libid3tag is FTBFS, and this is holding up KDE.

Also bumps user/kactivitymanagerd to 5.12.9 as a kactivities dep.

Omitted:

* Baloo: needs lmdb

* kdewebkit: needs Qt WebKit

* kfilemetadata: needs FFmpeg and its deps

* ktexteditor: needs libgit2

* Remove languagename patch, which backported a 5.57.0 feature to 5.54.0.

* Correctly escape newline in CMake invocation.

* distfiles.gentoo.org does not support HTTPS any more.

* Split -doc before -dev so that example .c files aren't considered -dev.

* Modernise / fix syntax.

* Remove patches for building against older Qt

* Split locale files

* Remove old CMake options that upstream no longer supports

The SDL 2 build system does not support dash-binsh when using the autotools
build system:

./configure: 1: ./configure: objects: not found
./configure: 1: ./configure: objects: not found
./configure: 1: ./configure: objects: not found
./configure: 1: ./configure: objects: not found
./configure: 1: ./configure: objects: not found
./configure: 1: ./configure: objects: not found
./configure: 1: ./configure: objects: not found
./configure: 1: ./configure: objects: not found

make: *** No rule to make target 'build/SDL.lo', needed by
'build/libSDL2.la'.  Stop.

Even when forcing shell to bash and running configure under bash, libtool
fails to work:

./libtool: 1569: ./libtool: preserve_args+= --quiet: not found

The CMake build system works with dash-binsh, so let's just use that.