Put back mistakenly removed #include.

tglsfdc · tglsfdc · commit 7a5d74b7dd4b · 2020-04-08T00:10:16.000-04:00
In commit 4dbcb3f I removed some code from parse_coerce.c, and also removed some apparently-no-longer-needed #includes. But removing datum.h broke some not-compiled-by-default code. Discussion: https://postgr.es/m/20200407205436.pyjhddw5bn5upvsu@development
diff --git a/src/backend/parser/parse_coerce.c b/src/backend/parser/parse_coerce.c
@@ -25,6 +25,7 @@
 #include "parser/parse_relation.h"
 #include "parser/parse_type.h"
 #include "utils/builtins.h"
+#include "utils/datum.h"		/* needed for datumIsEqual() */
 #include "utils/lsyscache.h"
 #include "utils/syscache.h"
 #include "utils/typcache.h"
