doc: update to latest help2man

Sync with version 1.47.3 which provides these significant changes:

- support for reproducible builds by using $SOURCE_DATE_EPOCH.
- Adjust spacing of italic text at roman/italic boundaries.

man/help2man

@@ -2,7 +2,7 @@
 
 # Generate a short man page from --help and --version output.
 # Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2009,
-# 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
+# 2010, 2011, 2012, 2013, 2014, 2015 Free Software Foundation, Inc.
 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -23,11 +23,12 @@
 use 5.008;
 use strict;
 use Getopt::Long;
+use Text::ParseWords qw(shellwords);
 use Text::Tabs qw(expand);
 use POSIX qw(strftime setlocale LC_ALL);
 
 my $this_program = 'help2man';
-my $this_version = '1.43.3';
+my $this_version = '1.47.3';
 
 sub _ { $_[0] }
 sub configure_locale
@@ -46,12 +47,13 @@ sub N_ { $_[0] }
 sub program_basename;
 sub get_option_value;
 sub convert_option;
+sub fix_italic_spacing;
 
 my $version_info = enc_user sprintf _(<<'EOT'), $this_program, $this_version;
 GNU %s %s
 
 Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2009, 2010,
-2011, 2012, 2013 Free Software Foundation, Inc.
+2011, 2012, 2013, 2014, 2015 Free Software Foundation, Inc.
 This is free software; see the source for copying conditions.  There is NO
 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 
@@ -125,7 +127,7 @@ my %include = ();
 my %replace = ();
 my %append = ();
 my %append_match = ();
-my @include = (); # retain order given in include file
+my @sections = ();  # retain order of include file or in-line *section*s
 
 # Process include file (if given).  Format is:
 #
@@ -190,9 +192,7 @@ while (@opt_include)
 		$hash = \%include;
 	    }
 
-	    push @include, $key
-		unless $include{$key} or $replace{$key} or $append{$key};
-
+	    push @sections, $key;
 	    next;
 	}
 
@@ -221,7 +221,7 @@ while (@opt_include)
 	    # handle options
 	    if (/^-/)
 	    {
-		local @ARGV = split;
+		local @ARGV = shellwords $_;
 		GetOptions %opt_def;
 	    }
 
@@ -247,11 +247,23 @@ for my $hash (\(%include, %replace, %append, %append_match))
 my $help_text   = get_option_value $ARGV[0], $help_option;
 $version_text ||= get_option_value $ARGV[0], $version_option;
 
+# By default the generated manual pages will include the current date.  This may
+# however be overriden by setting the environment variable $SOURCE_DATE_EPOCH
+# to an integer value of the seconds since the UNIX epoch.  This is primarily
+# intended to support reproducible builds (wiki.debian.org/ReproducibleBuilds)
+# and will additionally ensure that the output date string is UTC.
+my $epoch_secs = time;
+if (exists $ENV{SOURCE_DATE_EPOCH} and $ENV{SOURCE_DATE_EPOCH} =~ /^(\d+)$/)
+{
+    $epoch_secs = $1;
+    $ENV{TZ} = 'UTC';
+}
+
 # Translators: the following message is a strftime(3) format string, which in
 # the English version expands to the month as a word and the full year.  It
 # is used on the footer of the generated manual pages.  If in doubt, you may
 # just use %x as the value (which should be the full locale-specific date).
-my $date = enc strftime _("%B %Y"), localtime;
+my $date = enc strftime _("%B %Y"), localtime $epoch_secs;
 my $program = program_basename $ARGV[0];
 my $package = $program;
 my $version;
@@ -373,6 +385,7 @@ if ($help_text =~ s/^($PAT_USAGE):( +(\S+))(.*)((?:\n(?: {6}\1| *($PAT_USAGE_CON
 	s/\\fI$//;
 	s/^\./\\&./;
 
+	$_ = fix_italic_spacing $_;
 	$synopsis .= "$_\n";
     }
 
@@ -426,28 +439,37 @@ s/^Copyright +(?:\xa9|\([Cc]\))/Copyright \\(co/mg;
 while (length)
 {
     # Convert some standard paragraph names.
-    if (s/^($PAT_OPTIONS): *\n//o)
+    if (s/^($PAT_OPTIONS): *\n+//o)
     {
 	$sect = _('OPTIONS');
 	next;
     }
-    if (s/^($PAT_ENVIRONMENT): *\n//o)
+    if (s/^($PAT_ENVIRONMENT): *\n+//o)
     {
 	$sect = _('ENVIRONMENT');
 	next;
     }
-    if (s/^($PAT_FILES): *\n//o)
+    if (s/^($PAT_FILES): *\n+//o)
     {
 	$sect = _('FILES');
 	next;
     }
-    elsif (s/^($PAT_EXAMPLES): *\n//o)
+    elsif (s/^($PAT_EXAMPLES): *\n+//o)
     {
 	$sect = _('EXAMPLES');
 	next;
     }
 
-    # Copyright section
+    # Custom section indicated by a line containing "*Section Name*".
+    if (s/^\*(\w(.*\w)?)\* *\n+//)
+    {
+	$sect = uc $1;
+	$sect =~ tr/*/ /;  # also accept *Section*Name*
+	push @sections, $sect;
+	next;
+    }
+
+    # Copyright section.
     if (/^Copyright /)
     {
 	$sect = _('COPYRIGHT');
@@ -577,6 +599,8 @@ while (length)
 		)
 		($|[ ,;.)])			# space/punctuation after
 	    !$1\\fI$2\\fP$3!xmg;
+
+	    $_ = fix_italic_spacing $_;
 	}
 
 	# Escape remaining hyphens.
@@ -668,14 +692,17 @@ EOT
 
 # Section ordering.
 my @pre = (_('NAME'), _('SYNOPSIS'), _('DESCRIPTION'), _('OPTIONS'),
-    _('ENVIRONMENT'), _('FILES'), _('EXAMPLES'));
-
-my @post = (_('AUTHOR'), _('REPORTING BUGS'), _('COPYRIGHT'), _('SEE ALSO'));
-my $filter = join '|', @pre, @post;
+    _('EXAMPLES'));
+my @post = (_('ENVIRONMENT'), _('FILES'), _('AUTHOR'),
+    _('REPORTING BUGS'), _('COPYRIGHT'), _('SEE ALSO'));
+my %filter = map { $_ => 1 } @pre, @post;
 
 # Output content.
-for my $sect (@pre, (grep ! /^($filter)$/o, @include), @post)
+my %done;
+for my $sect (@pre, (grep !$filter{$_}, @sections), @post)
 {
+    next if $done{$sect}++;  # ignore duplicates
+    next unless $include{$sect};
     if ($include{$sect})
     {
 	my $quote = $sect =~ /\W/ ? '"' : '';
@@ -751,3 +778,12 @@ sub convert_option
 
     $_;
 }
+
+# Insert spacing escape characters \, and \/ before and after italic text.  See
+# http://www.gnu.org/software/groff/manual/html_node/Ligatures-and-Kerning.html
+sub fix_italic_spacing
+{
+    local $_ = shift;
+    s!\\fI(.*?)\\f([BRP])!\\fI\\,$1\\/\\f$2!g;
+    return $_;
+}