time-util: let's make xstrftime() useful for everybody, even if we only have a single user so far.

src/shared/time-util.h

@@ -107,3 +107,5 @@ int get_timezones(char ***l);
 bool timezone_is_valid(const char *name);
 
 clockid_t clock_boottime_or_monotonic(void);
+
+#define xstrftime(buf, fmt, tm) assert_se(strftime(buf, ELEMENTSOF(buf), fmt, tm) > 0)

src/timedate/timedatectl.c

@@ -38,8 +38,6 @@
 #include "pager.h"
 #include "time-dst.h"
 
-#define xstrftime(buf, fmt, tm) assert_se(strftime(buf, sizeof(buf), fmt, tm) > 0)
-
 static bool arg_no_pager = false;
 static bool arg_ask_password = true;
 static BusTransport arg_transport = BUS_TRANSPORT_LOCAL;