Correctly print time_t.

Index: src/rrd_graph_helper.c
--- src/rrd_graph_helper.c.orig
+++ src/rrd_graph_helper.c
@@ -1904,7 +1904,7 @@ static int parse_shift(
 #if defined _WIN32 && SIZEOF_TIME_T == 8    /* in case of __MINGW64__, _WIN64 and _MSC_VER >= 1400 (ifndef _USE_32BIT_TIME_T) */
         dprintf("SHIFTBY : %lli\n", gdp->shval);    /* argument 3 has type 'time_t {aka long long int}' */
 #else
-        dprintf("SHIFTBY : %li\n", gdp->shval);
+        dprintf("SHIFTBY : %lli\n",(long long)gdp->shval); /* argument 3 has type 'time_t' */
 #endif
     }
     dprintf("=================================\n");