lib: lib-signals: Removed explicit notification of ioloop change through lib_signals_reset_ioloop() in favor of implicit method. Before, if the ioloop changed, the application had to explicitly notify lib-signals using lib_signals_reset_ioloop(). This is error-prone and requires doing this all over the Dovecot code base. Now, lib-signals registers an ioloop switch callback that deals with this implicitly. The application can detach lib-signals from the ioloop explicitly if delayed signal handling is not required/desired in the new ioloop. Specific delayed signal handlers can be exempt from this automated behavior using a flag, meaning that such signal handlers need to be moved between ioloops explicitly.

lib: Add lib_signals_syscall_error()

Marked functions parameters that are allowed to be NULL. Some APIs were also changed. The non-obvious APIs where NULL parameter was changed to "" are master_service_init() and auth_master_user_list_init(). These checks can currently be enabled only on a patched clang: http://llvm.org/bugs/show_bug.cgi?id=6786

lib_signals_set_handler(): Changed API to take flags instead of boolean. This is still compatible with the old API, because using FALSE/TRUE as the flags still maps to the same behavior.

Added signal_term_counter that keeps track of how many terminal signals have been received.

Compile fix to NetBSD: Don't use si_code which is a macro. Patch by Tatsuyoshi. --HG-- branch : HEAD

When a process is killed, show the signal code and the sending process's pid and uid. --HG-- branch : HEAD

lib-signals: Changed callback API to return siginfo_t. --HG-- branch : HEAD

Added lib_signals_reset_ioloop() for handling signals with multiple ioloops. --HG-- branch : HEAD

Changed .h ifdef/defines to use <NAME>_H format. --HG-- branch : HEAD

Type safe callbacks weren't as easy as I thought. Only callback(void *context) can be handled generically. Others can be handled specially, but only if all the parameters are pointers, otherwise eg. int parameter can be replaced with long without compiler giving any warnings. --HG-- branch : HEAD

Added context parameter type safety checks for most callback APIs. --HG-- branch : HEAD

And s/lib_signals_ignore_signal/lib_signals_ignore/ --HG-- branch : HEAD

Added lib_signals_ignore_signal() and made lib_signals_set_handler() with NULL handler not restart syscall. --HG-- branch : HEAD

Added "bool" type and changed all ints that were used as booleans to bool. --HG-- branch : HEAD

Implemented new signal handling framework, which makes handling signals much easier. --HG-- branch : HEAD

Add signal counters to USR1 and USR2 signals too. --HG-- branch : HEAD

Changed lib_signal_hup to lib_signal_hup_count. --HG-- branch : HEAD

Initial revision --HG-- branch : HEAD