Make type 'regproc' binary-compatible with int4 and oid,

so that it has some SQL operators available.  It's difficult to write
automated tests of a data type that you haven't even got == for...

src/include/parser/parse_coerce.h

@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: parse_coerce.h,v 1.8 1999/02/13 05:25:54 thomas Exp $
+ * $Id: parse_coerce.h,v 1.9 1999/03/10 05:05:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -78,12 +78,15 @@ typedef enum CATEGORY
 		|| ((a) == TEXTOID && (b) == BPCHAROID) \
 		|| ((a) == TEXTOID && (b) == VARCHAROID) \
 		|| ((a) == OIDOID && (b) == INT4OID) \
-		|| ((a) == INT4OID && (b) == TIMESTAMPOID) \
+		|| ((a) == OIDOID && (b) == REGPROCOID) \
+		|| ((a) == INT4OID && (b) == OIDOID) \
+		|| ((a) == INT4OID && (b) == REGPROCOID) \
+		|| ((a) == REGPROCOID && (b) == OIDOID) \
+		|| ((a) == REGPROCOID && (b) == INT4OID) \
 		|| ((a) == ABSTIMEOID && (b) == TIMESTAMPOID) \
 		|| ((a) == ABSTIMEOID && (b) == INT4OID) \
 		|| ((a) == TIMESTAMPOID && (b) == ABSTIMEOID) \
 		|| ((a) == TIMESTAMPOID && (b) == INT4OID) \
-		|| ((a) == INT4OID && (b) == OIDOID) \
 		|| ((a) == INT4OID && (b) == ABSTIMEOID) \
 		|| ((a) == INT4OID && (b) == TIMESTAMPOID) \
 		|| ((a) == RELTIMEOID && (b) == INT4OID) \