All three of these gadgets are ports of the existing modules of the same name and are contained within those directories. Once the move from shelves -> bryce and gadcon->gadgets is complete, backlight and mixer will likely need to go into the sysinfo gadget.
this is the correct way to write a build system. one toplevel Makefile.am with the rest of the directories having include Makefile.mk files.
additional authors:
Iván Briano <ivan.briano@intel.com>