Fix compiler warnings due to commit cc4fede

Author: adunstan

src/include/utils/date.h

@@ -17,6 +17,7 @@
 #include <math.h>
 
 #include "fmgr.h"
+#include "pgtime.h"
 #include "datatype/timestamp.h"
 
 typedef int32 DateADT;