Move some things from builtins.h to new header files

This avoids that builtins.h has to include additional header files.

src/backend/commands/extension.c

@@ -59,6 +59,7 @@
 #include "utils/rel.h"
 #include "utils/snapmgr.h"
 #include "utils/tqual.h"
+#include "utils/varlena.h"
 
 
 /* Globally visible state variables */

src/backend/commands/indexcmds.c

@@ -51,6 +51,7 @@
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
+#include "utils/regproc.h"
 #include "utils/snapmgr.h"
 #include "utils/syscache.h"
 #include "utils/tqual.h"

src/backend/commands/sequence.c

@@ -41,6 +41,7 @@
 #include "utils/lsyscache.h"
 #include "utils/resowner.h"
 #include "utils/syscache.h"
+#include "utils/varlena.h"
 
 
 /*

src/backend/commands/tablespace.c

@@ -82,6 +82,7 @@
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/tqual.h"
+#include "utils/varlena.h"
 
 
 /* GUC variables */

src/backend/commands/variable.c

@@ -30,6 +30,7 @@
 #include "utils/syscache.h"
 #include "utils/snapmgr.h"
 #include "utils/timestamp.h"
+#include "utils/varlena.h"
 #include "mb/pg_wchar.h"
 
 /*