kernel-doc: bugfix - empty line in Example section

If you have a section named "Example" that contains an empty line,
attempting to generate htmldocs give you the error:

/path/Documentation/DocBook/kernel-api.xml:3455: parser error : Opening and ending tag mismatch: programlisting line 3449 and para
   </para><para>
          ^
/path/Documentation/DocBook/kernel-api.xml:3473: parser error : Opening and ending tag mismatch: para line 3467 and programlisting
</programlisting></informalexample>
                 ^
/path/Documentation/DocBook/kernel-api.xml:3678: parser error : Opening and ending tag mismatch: programlisting line 3672 and para
   </para><para>
          ^
/path/Documentation/DocBook/kernel-api.xml:3701: parser error : Opening and ending tag mismatch: para line 3690 and programlisting
</programlisting></informalexample>
                 ^
unable to parse
/path/Documentation/DocBook/kernel-api.xml

Essentially, the script attempts to close a <programlisting> with a
closing tag for a <para> block.  This patch corrects the problem by
simply not outputting anything extra when we're dumping pre-formatted
text, since the empty line will be rendered correctly anyway.

Signed-off-by: Daniel Santos <daniel.santos@pobox.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/kernel-doc

@@ -230,6 +230,7 @@ my $dohighlight = "";
 
 my $verbose = 0;
 my $output_mode = "man";
+my $output_preformatted = 0;
 my $no_doc_sections = 0;
 my %highlights = %highlights_man;
 my $blankline = $blankline_man;
@@ -460,7 +461,9 @@ sub output_highlight {
 
     foreach $line (split "\n", $contents) {
 	if ($line eq ""){
-	    print $lineprefix, local_unescape($blankline);
+	    if (! $output_preformatted) {
+		print $lineprefix, local_unescape($blankline);
+	    }
 	} else {
 	    $line =~ s/\\\\\\/\&/g;
 	    if ($output_mode eq "man" && substr($line, 0, 1) eq ".") {
@@ -643,10 +646,12 @@ sub output_section_xml(%) {
 	print "<title>$section</title>\n";
 	if ($section =~ m/EXAMPLE/i) {
 	    print "<informalexample><programlisting>\n";
+	    $output_preformatted = 1;
 	} else {
 	    print "<para>\n";
 	}
 	output_highlight($args{'sections'}{$section});
+	$output_preformatted = 0;
 	if ($section =~ m/EXAMPLE/i) {
 	    print "</programlisting></informalexample>\n";
 	} else {
@@ -949,10 +954,12 @@ sub output_blockhead_xml(%) {
 	}
 	if ($section =~ m/EXAMPLE/i) {
 	    print "<example><para>\n";
+	    $output_preformatted = 1;
 	} else {
 	    print "<para>\n";
 	}
 	output_highlight($args{'sections'}{$section});
+	$output_preformatted = 0;
 	if ($section =~ m/EXAMPLE/i) {
 	    print "</para></example>\n";
 	} else {
@@ -1028,10 +1035,12 @@ sub output_function_gnome {
 	print "<simplesect>\n <title>$section</title>\n";
 	if ($section =~ m/EXAMPLE/i) {
 	    print "<example><programlisting>\n";
+	    $output_preformatted = 1;
 	} else {
 	}
 	print "<para>\n";
 	output_highlight($args{'sections'}{$section});
+	$output_preformatted = 0;
 	print "</para>\n";
 	if ($section =~ m/EXAMPLE/i) {
 	    print "</programlisting></example>\n";