build: Add -Iinclude to libinput and its tools
Various files use #include <linux/input.h> and, if the system input.h is too old, will fail to compile. Use the internal copy by adding -Iinclude to the build command lines. This was the case in the old autotools build system. Signed-off-by:Philip Withnall <withnall@endlessm.com> Signed-off-by:
Peter Hutterer <peter.hutterer@who-t.net>