Excludes user/kpat, which requires a bunch of Perl packages.

Excludes user/rocs since it requires Qt WebKit.

* This also makes wayland required in kscreenlocker again - otherwise
  plasma-workspace FTBFS

* header.patch: Backports from 5.17 to build against Qt 5.12

* session-conflict.patch: Ensure the Wayland session is clearly marked as
  such, so that users are aware it is unsupported.

* Define _BSD_SOURCE in <rpc/types.h> for building against in ISO C mode

* Fix location of <endian.h>

* Remove upstreamed musl compatibility patch.

* 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.