cmake: gr-dtv: fix internal GR component dependencies
cmake: OSS is not for APPLE or WINDOWS.
cmake: Use APPLE, not matching Darwin
cmake: modtool: allow the use of a MODULES_DIR to specify where cmake modules are installed.
cmake: modtool: On Apple only, set install name and use rpath correctly.
cmake: modtool: make sure our local CMake Modules path comes first.
cmake: modtool: update copyright date.