repmgrd: fix parsing of -d/--daemonize option

The getopt API doesn't cope well with optional arguments to short form options,
e.g. "-o foo", so we need to check the next argument value to see whether it looks
like an option or an actual argument value.

repmgrd.h

@@ -11,6 +11,7 @@
 #include "portability/instr_time.h"
 
 #define OPT_NO_PID_FILE                  1000
+#define OPT_DAEMONIZE                    1001
 
 extern volatile sig_atomic_t got_SIGHUP;
 extern MonitoringState monitoring_state;