Notes for gr-gsm - reproducible builds result

Version annotated: 0.42.2-1
Identified issues:
Identifier: timestamp_added_by_gnuradio_grcc
Description .grc files are compiled by grcc and adds a Generated timestamp header that
varies by timezone.
Code is in ./grc/core/generator/flow_graph.tmpl

Our notes about issues affecting packages are stored in notes.git and are targeted at packages in Debian in 'unstable/amd64' (unless they say otherwise).