Fix compilation with enabled EVENT_INPUT

Need to move the definition to the toplevel cmake file, since sources
are no longer compiled on directory level (individual libs per dir).

CMakeLists.txt

@@ -132,6 +132,7 @@ if(EVENT_INPUT)
             message(WARNING "UDev not found, event input is disabled!")
             set(EVENT_INPUT 0)
         else()
+            add_definitions(-DWITH_EVENTINPUT)
             set(EVENT_INPUT_LIBRARIES ${UDEV_LIBRARIES})
             message(STATUS "event-based input enabled. Using ${UDEV_LIBRARIES}")
         endif()

src/Input/CMakeLists.txt

@@ -19,7 +19,7 @@ set(SOURCES
 	FGJoystickInput.cxx
 	FGKeyboardInput.cxx
 	FGMouseInput.cxx
-	input.cxx	
+	input.cxx
 	)
 
 set(HEADERS
@@ -37,7 +37,6 @@ if(EVENT_INPUT)
 	list(APPEND SOURCES ${EVENT_INPUT_SOURCES})
 	list(APPEND SOURCES ${EVENT_INPUT_HEADERS})
 	include_directories(${UDEV_INCLUDE_DIR})
-	add_definitions(-DWITH_EVENTINPUT)
 endif()
 
 set(FGJS_SOURCES