This ensures that we get a warning if the config header is not included
instead of compiling the code as if it was disabled. Interestingly, some
checks already used #if KWIN_BUILD_*, so those were generating -Wundef
warnings when the feature is disabled. Commit 886173cab assumed that all
those features were already 01, so this unbreaks the build if any of the
features is disabled.
Fixes: 886173cab ("Reduce ifdefs in Workspace::supportInformation()")
d789ecc6d1