Instead of immediately shutting down the application, it is
better to try to break the processing queue first, and stop
the execution immediately if second SIGINT is received.
The printf() writes the text into stdout, which may be undesirable
in some use cases. Moreover, the printed information was redundant.
So, let's drop such calls.
Since this change, the libosmogapk uses the Osmocom logging
framework. By default, logging is disabled and could be enabled
by the external applications calling the osmo_gapk_log_init()
with a desired log target as an argument.
Since GAPK package contains a library and the representative
osmo-gapk application, the 'main.c' looks a bit confusing. Let's
use the common naming scheme.
Vadim Yanitskiy