desktop-shell: allow setting the work area calculation function from the API

2 jobs for master in 2 minutes and 40 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
failed #77840
build-native-autotools

00:02:40

failed #77841
build-native-meson

00:02:29

 
Name Stage Failure
failed
build-native-autotools Build
and LIBEVDEV_LIBS to avoid the need to call pkg-config.
See the pkg-config man page for more details.
Uploading artifacts...
WARNING: build-*/weston-*.tar.xz: no matching files
build-*/*.log: found 1 matching files

WARNING: build-*/logs: no matching files
prefix-*: found 54 matching files

Uploading artifacts to coordinator... ok
id=77840 responseStatus=201 Created token=svtRaZy_
ERROR: Job failed: exit code 1
failed
build-native-meson Build

meson.build:157:0: ERROR: Dependency "libevdev" not found, tried pkgconfig

A full log can be found at /builds/myfreeweb/weston/build-weston-3be2780e97c0352caed99cc1ef1e3ad912e5ac95-77841/meson-logs/meson-log.txt
Uploading artifacts...
WARNING: build-meson/meson-logs: no matching files
prefix-*: found 54 matching files

Uploading artifacts to coordinator... ok
id=77841 responseStatus=201 Created token=k934LJs-
ERROR: Job failed: exit code 1