Linux: Add an evdev based controller backend, to replace SDL.

CMakeTests/FindLibevdev.cmake

@@ -0,0 +1,33 @@
+# - Try to find libevdev
+# Once done this will define
+#  LIBEVDEV_FOUND - System has libevdev
+#  LIBEVDEV_INCLUDE_DIRS - The libevdev include directories
+#  LIBEVDEV_LIBRARIES - The libraries needed to use libevdev
+
+find_package(PkgConfig)
+pkg_check_modules(PC_LIBEVDEV QUIET libevdev)
+
+FIND_PATH(
+    LIBEVDEV_INCLUDE_DIR libevdev/libevdev.h
+    HINTS ${PC_LIBEVDEV_INCLUDEDIR} ${PC_LIBEVDEV_INCLUDE_DIRS}
+    /usr/include
+    /usr/local/include
+    ${LIBEVDEV_PATH_INCLUDES}
+)
+
+FIND_LIBRARY(
+    LIBEVDEV_LIBRARY
+    NAMES evdev libevdev
+    HINTS ${PC_LIBEVDEV_LIBDIR} ${PC_LIBEVDEV_LIBRARY_DIRS}
+    PATHS ${ADDITIONAL_LIBRARY_PATHS}
+        ${LIBEVDEV_PATH_LIB}
+)
+
+set(LIBEVDEV_LIBRARIES ${LIBEVDEV_LIBRARY} )
+set(LIBEVDEV_INCLUDE_DIRS ${LIBEVDEV_INCLUDE_DIR} )
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(libevdev  DEFAULT_MSG
+                                  LIBEVDEV_LIBRARY LIBEVDEV_INCLUDE_DIR)
+
+mark_as_advanced(LIBEVDEV_INCLUDE_DIR LIBEVDEV_LIBRARY )