cmake: Remove redundant include_directories()

libkwin is linked against imported XKB::XKB target. Thus the
include_directories() is redundant.

CMakeLists.txt

@@ -358,8 +358,6 @@ if (KWIN_BUILD_XRENDER_COMPOSITING)
     set(KWIN_HAVE_XRENDER_COMPOSITING 1)
 endif()
 
-include_directories(${XKB_INCLUDE_DIR})
-
 set(HAVE_EPOXY_GLX ${epoxy_HAS_GLX})
 
 # for things that are also used by kwin libraries

[Derek Christ]

My build fails since this commit with

/home/derek/KDE/src/kwin/xkb.h:12:10: schwerwiegender Fehler: xkbcommon/xkbcommon.h: Datei oder Verzeichnis nicht gefunden
   12 | #include <xkbcommon/xkbcommon.h>

is this correct?

[Nate Graham]

Same:

[  9%] Building CXX object kcmkwin/kwinrules/CMakeFiles/KWinRulesObjects.dir/__/__/cursor.cpp.o
In file included from /home/nate/kde/src/kwin/keyboard_input.h:13,
                 from /home/nate/kde/src/kwin/cursor.cpp:13:
/home/nate/kde/src/kwin/xkb.h:12:10: fatal error: xkbcommon/xkbcommon.h: No such file or directory
   12 | #include <xkbcommon/xkbcommon.h>
      |          ^~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.

I have all xkb dev packages including for libxkbcommon, so I don't think this is an issue of missing dependencies.

Reverting.