Various fixes in the logic of XML functions:

- Add new SQL command SET XML OPTION (also available via regular GUC) to
  control the DOCUMENT vs. CONTENT option in implicit parsing and
  serialization operations.

- Subtle corrections in the handling of the standalone property in
  xmlroot().

- Allow xmlroot() to work on content fragments.

- Subtle corrections in the handling of the version property in
  xmlconcat().

- Code refactoring for producing XML declarations.

src/backend/parser/keywords.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/keywords.c,v 1.183 2007/01/23 05:07:18 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/keywords.c,v 1.184 2007/01/25 11:53:51 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -380,6 +380,7 @@ static const ScanKeyword ScanKeywords[] = {
 	{"without", WITHOUT},
 	{"work", WORK},
 	{"write", WRITE},
+	{"xml", XML_P},
 	{"xmlattributes", XMLATTRIBUTES},
 	{"xmlconcat", XMLCONCAT},
 	{"xmlelement", XMLELEMENT},