.conf: don't rely on mtime to determine if service needs reloading

Until now Finit has used mtime to determine if a file has been changed,
or simply touched to request reload, when `initctl reload` is called.
Using mtime for this purpose is a monumentally bad idea since time can
be changed at any point: a user may adjust the time, NTP continously
tunes the clock, and time stamps are stored as the walltime.  So if we
compare timestamps against the last time we (booted or) did reload, we
would miss .conf file changes.

This patch replaces the mtime mistake with an inotify watcher for the
following files: /etc/finit.d/*.conf, /etc/finit.d/available/*.conf,
and /etc/finit.conf.  All file changes between (bootstraps and) calls
to `initctl reload` are tracked, like the mtime backend it replaces.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

src/conf.h

@@ -31,11 +31,14 @@ extern struct rlimit global_rlimit[];
 int   str2rlim(char *str);
 char *rlim2str(int rlim);
 
+int  conf_init            (void);
+void conf_reload          (void);
+int  conf_changed         (char *file);
+int  conf_monitor         (uev_ctx_t *ctx);
+
 void conf_parse_cmdline   (void);
 int  conf_parse_runlevels (char *runlevels);
 void conf_parse_cond      (svc_t *svc, char *cond);
-int  conf_parse_config    (void);
-void conf_reload_dynamic  (void);
 
 #endif	/* FINIT_CONF_H_ */