Only compile VirtualTerminal if libinput is found

The implementation of VirtualTerminal is too linux specific and doesn't
compile on e.g. freebsd. Currently the most usage is in combination with
libinput. Only usage is:
* libinput related functionality in InputRedirection
* backends without custom input handling

Thus binding the feature to whether libinput is available is currently
the least invasive approach to get it compile on non-Linux.

In the long run this needs a different solution. The functionality
provided by VirtualTerminal is required and without the backends don't
work. It's needed to get notified about VT switches, when KWin needs to
stop rendering. So a solution for non-Linux needs to be found if
non-Linux wants to provide Wayland in future.

REVIEW: 126182

CMakeLists.txt

@@ -376,7 +376,6 @@ set(kwin_KDEINIT_SRCS
     abstract_egl_backend.cpp
     eglonxbackend.cpp
     abstract_backend.cpp
-    virtual_terminal.cpp
     shell_client.cpp
     wayland_server.cpp
     wayland_cursor_theme.cpp
@@ -421,6 +420,7 @@ if(HAVE_INPUT)
         libinput/connection.cpp
         libinput/events.cpp
         libinput/libinput_logging.cpp
+        virtual_terminal.cpp
     )
 endif()
 

backends/CMakeLists.txt

@@ -1,3 +1,4 @@
+if(HAVE_INPUT)
     if(HAVE_DRM)
         add_subdirectory(drm)
     endif()
@@ -5,6 +6,7 @@ add_subdirectory(fbdev)
     if(HAVE_LIBHYBRIS)
         add_subdirectory(hwcomposer)
     endif()
+endif()
 add_subdirectory(virtual)
 add_subdirectory(wayland)
 if(X11_XCB_FOUND)

input.cpp

@@ -31,11 +31,11 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "workspace.h"
 #if HAVE_INPUT
 #include "libinput/connection.h"
+#include "virtual_terminal.h"
 #endif
 #include "abstract_backend.h"
 #include "shell_client.h"
 #include "wayland_server.h"
-#include "virtual_terminal.h"
 #include <KWayland/Server/display.h>
 #include <KWayland/Server/fakeinput_interface.h>
 #include <KWayland/Server/seat_interface.h>
@@ -939,6 +939,7 @@ void InputRedirection::processKeyboardKey(uint32_t key, InputRedirection::Keyboa
         emit keyboardModifiersChanged(keyboardModifiers(), oldMods);
     }
     // check for vt-switch
+#if HAVE_INPUT
     if (VirtualTerminal::self()) {
         const xkb_keysym_t keysym = m_xkb->toKeysym(key);
         if (state == KWin::InputRedirection::KeyboardKeyPressed &&
@@ -947,6 +948,7 @@ void InputRedirection::processKeyboardKey(uint32_t key, InputRedirection::Keyboa
             return;
         }
     }
+#endif
 
 
     if (waylandServer()->isScreenLocked()) {