Generate the long/short option cross-table.

* build-aux/cross-options.pl: New.
* doc/Makefile.am (cross-options.texi): New.
* doc/bison.texinfo: Use it.

build-aux/cross-options.pl

@@ -0,0 +1,32 @@
+#! /usr/bin/env perl
+
+use warnings;
+use 5.005;
+use strict;
+
+my %option;
+while (<>)
+{
+    if (/^\s*(?:(-\w), )?(--[-\w]+)(\[?)(=[-\w]+)?\]?/)
+    {
+	my ($short, $long, $opt, $arg) = ($1, $2, $3, $4);
+	$short = defined $short ? '@option{' . $short . '}' : '';
+	if ($arg)
+	{
+	    $arg =~ s/^=//;
+	    $arg = '@var{' . lc ($arg) . '}';
+	    $arg = '[' . $arg . ']'
+		if defined $opt;
+	    $option{"$long=$arg"} = "$short $arg";
+	}
+	else
+	{
+	    $option{"$long"} = "$short";
+	}
+    }
+}
+
+foreach my $long (sort keys %option)
+{
+    printf "\@item %-40s \@tab %s\n", '@option{' . $long . '}', $option{$long};
+}