cmdline parsing: move into a dedicated perl module

With this change, we delegate most of the automake and aclocal code
for command-line options parsing to a new module "Automake::Getopt".
This allows better code sharing between automake and aclocal, and
also with Autoconf, which will sync the new module from us.  See
also autoconf commit 'v2.68-120-gf4be358' (2012-01-17, "getopt: new
Autom4te::Getopt module"), and this mailing list discussion:
<http://lists.gnu.org/archive/html/autoconf-patches/2012-01/msg00033.html>

This change might interact with the behaviour described in automake
bug#7434; for example, starting from now, "automake -Wfoo --version"
will cause automake to emit diagnostic like "unknown warning
category 'foo'" before actually printing the version number and
exiting.  This is not a big deal in practice, and the code sharing
and simplifications introduced by this patch is certainly worth it.
Still, we should revisited the issue in the future.

* lib/Automake/Getopt.pm: New module, basically a slightly-edited
copy of the 'lib/Autom4te/Getopt.pm' file from the autoconf devel
repository (commit v2.68-120-gf4be358).  It defines and exports ...
(parse_options): ... this new function.
* automake.in (parse_arguments): Use the new function.
* aclocal.in (parse_arguments): Likewise.
* lib/Automake/Makefile.am (dist_perllib_DATA): Add the new file.
* tests/getopt.test: Remove.
* tests/list-of-tests.mk: Update.

2 files changed, 116 insertions, 0 deletions

diff --git a/lib/Automake/Getopt.pm b/lib/Automake/Getopt.pm
new file mode 100644
index 000000000..84cee5e4a
--- /dev/null
+++ b/lib/Automake/Getopt.pm
@@ -0,0 +1,115 @@
+# Copyright (C) 2012 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
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package Automake::Getopt;
+
+=head1 NAME
+
+Automake::Getopt - GCS conforming parser for command line options
+
+=head1 SYNOPSIS
+
+  use Automake::Getopt;
+
+=head1 DESCRIPTION
+
+Export a function C<parse_options>, performing parsing of command
+line options in conformance to the GNU Coding standards.
+
+=cut
+
+use 5.006_002;
+use strict;
+use warnings FATAL => 'all';
+use Exporter ();
+use Getopt::Long ();
+use Automake::ChannelDefs qw/fatal/;
+use Carp qw/croak confess/;
+
+use vars qw (@ISA @EXPORT);
+@ISA = qw (Exporter);
+@EXPORT= qw/getopt/;
+
+=item C<parse_options (%option)>
+
+Wrapper around C<Getopt::Long>, trying to conform to the GNU
+Coding Standards for error messages.
+
+=cut
+
+sub parse_options (%)
+{
+  my %option = @_;
+
+  Getopt::Long::Configure ("bundling", "pass_through");
+  # Unrecognized options are passed through, so GetOption can only fail
+  # due to internal errors or misuse of options specification.
+  Getopt::Long::GetOptions (%option)
+    or confess "error in options specification (likely)";
+
+  if (@ARGV && $ARGV[0] =~ /^-./)
+    {
+      my %argopts;
+      for my $k (keys %option)
+	{
+	  if ($k =~ /(.*)=s$/)
+	    {
+	      map { $argopts{(length ($_) == 1)
+			     ? "-$_" : "--$_" } = 1; } (split (/\|/, $1));
+	    }
+	}
+      if ($ARGV[0] eq '--')
+	{
+	  shift @ARGV;
+	}
+      elsif (exists $argopts{$ARGV[0]})
+	{
+	  fatal ("option `$ARGV[0]' requires an argument\n"
+		 . "Try `$0 --help' for more information.");
+	}
+      else
+	{
+	  fatal ("unrecognized option `$ARGV[0]'.\n"
+		 . "Try `$0 --help' for more information.");
+	}
+    }
+}
+
+=back
+
+=head1 SEE ALSO
+
+L<Getopt::Long>
+
+=cut
+
+1; # for require
+
+### Setup "GNU" style for perl-mode and cperl-mode.
+## Local Variables:
+## perl-indent-level: 2
+## perl-continued-statement-offset: 2
+## perl-continued-brace-offset: 0
+## perl-brace-offset: 0
+## perl-brace-imaginary-offset: 0
+## perl-label-offset: -2
+## cperl-indent-level: 2
+## cperl-brace-offset: 0
+## cperl-continued-brace-offset: 0
+## cperl-label-offset: -2
+## cperl-extra-newline-before-brace: t
+## cperl-merge-trailing-else: nil
+## cperl-continued-statement-offset: 2
+## End:
diff --git a/lib/Automake/Makefile.am b/lib/Automake/Makefile.am
index 980502462..ac9356a49 100644
--- a/lib/Automake/Makefile.am
+++ b/lib/Automake/Makefile.am
@@ -25,6 +25,7 @@ dist_perllib_DATA = \
   DisjConditions.pm \
   FileUtils.pm \
   General.pm \
+  Getopt.pm \
   Item.pm \
   ItemDef.pm \
   Location.pm \