Block SIGALRM during syscalls
In various places, including the DBUS calls which can take some time, if a SIGALRM triggers, the call will fail.
To prevent this from happening, add some wrappers sure to block the SIGALRM signal before various system/DBus calls.
cc @ofourdan: this is your branch, slightly modified to namespace to signals_block
/release
. And then my crazy macro on top so you don't get blamed for that