util: use /dev/rtc symlink if possible before we go searching for a suitable device

TODO

@@ -113,7 +113,7 @@ Features:
 
 * readahead: check whether a btrfs volume includes ssd by checking mount flag "ssd"
 
-* support sd_notify() style notification when reload begins (RELOADING=1), reload is finished (READY=1)
+* support sd_notify() style notification when reload begins (RELOADING=1), reload is finished (READY=1), and add ReloadSignal= then to use in combination
 
 * support sd_notify() style notification when shutting down, to make auto-exit bus services work (STOPPING=1)
 

src/util.c

@@ -5235,8 +5235,14 @@ int rtc_open(int flags) {
         int fd;
         DIR *d;
 
-        /* We open the first RTC which has hctosys=1 set. If we don't
-         * find any we just take the first one */
+        /* First, we try to make use of the /dev/rtc symlink. If that
+         * doesn't exist, we open the first RTC which has hctosys=1
+         * set. If we don't find any we just take the first RTC that
+         * exists at all. */
+
+        fd = open("/dev/rtc", flags);
+        if (fd >= 0)
+                return fd;
 
         d = opendir("/sys/class/rtc");
         if (!d)