pgrep, kill: use sigqueue to pass integer value with the signal.
This changeset queue will help in passing an integer value with the signal.
This uses sigqueue instead of kill when the command line option -q/--queue <value> is specified.
I am not sure if sigqueue is supported on all the platforms. I have tested this with RHEL 7.2 and it works fine.
Please review and left me know if any changes are required.