Avoid maintaining three separate copies of the error codes list.

src/pl/plpgsql/src/plerrcodes.h, src/include/utils/errcodes.h, and a
big chunk of errcodes.sgml are now automatically generated from a single
file, src/backend/utils/errcodes.txt.

Jan Urbański, reviewed by Tom Lane.

src/backend/utils/generate-errcodes.pl

@@ -0,0 +1,41 @@
+#!/usr/bin/perl
+#
+# Generate the errcodes.h header from errcodes.txt
+# Copyright (c) 2000-2011, PostgreSQL Global Development Group
+
+use warnings;
+use strict;
+
+print "/* autogenerated from src/backend/utils/errcodes.txt, do not edit */\n";
+print "/* there is deliberately not an #ifndef ERRCODES_H here */\n";
+
+open my $errcodes, $ARGV[0] or die;
+
+while (<$errcodes>) {
+    chomp;
+
+    # Skip comments
+    next if /^#/;
+    next if /^\s*$/;
+
+    # Emit a comment for each section header
+    if (/^Section:(.*)/) {
+		my $header = $1;
+		$header =~ s/^\s+//;
+		print "\n/* $header */\n";
+		next;
+	}
+
+    die "unable to parse errcodes.txt" unless /^([^\s]{5})\s+[EWS]\s+([^\s]+)/;
+
+    (my $sqlstate, my $errcode_macro) = ($1, $2);
+
+    # Split the sqlstate letters
+    $sqlstate = join ",", split "", $sqlstate;
+    # And quote them
+    $sqlstate =~ s/([^,])/'$1'/g;
+
+    print "#define $errcode_macro MAKE_SQLSTATE($sqlstate)\n";
+}
+
+close $errcodes;