old_contents: ##############################################################################
  # Copyright (c) 2013-2018, Lawrence Livermore National Security, LLC.
  # Produced at the Lawrence Livermore National Laboratory.
  #
  # This file is part of Spack.
  # Created by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
  # LLNL-CODE-647188
  #
  # For details, see https://github.com/spack/spack
  # Please also see the NOTICE and LICENSE files for our notice and the LGPL.
  #
  # This program is free software; you can redistribute it and/or modify
  # it under the terms of the GNU Lesser General Public License (as
  # published by the Free Software Foundation) version 2.1, February 1999.
  #
  # 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 terms and
  # conditions of the GNU Lesser General Public License for more details.
  #
  # You should have received a copy of the GNU Lesser General Public
  # License along with this program; if not, write to the Free Software
  # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  ##############################################################################
  from spack import *
  
  
  class Libunwind(AutotoolsPackage):
      """A portable and efficient C programming interface (API) to determine
         the call-chain of a program."""
      homepage = "http://www.nongnu.org/libunwind/"
      url      = "http://download.savannah.gnu.org/releases/libunwind/libunwind-1.1.tar.gz"
  
      conflicts('platform=darwin',
                msg='Non-GNU libunwind needs ELF libraries Darwin does not have')
  
      version('1.2.1', '06ba9e60d92fd6f55cd9dadb084df19e')
      version('1.1', 'fb4ea2f6fbbe45bf032cd36e586883ce')
  
      provides('unwind')
  
new_contents: ##############################################################################
  # Copyright (c) 2013-2018, Lawrence Livermore National Security, LLC.
  # Produced at the Lawrence Livermore National Laboratory.
  #
  # This file is part of Spack.
  # Created by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
  # LLNL-CODE-647188
  #
  # For details, see https://github.com/spack/spack
  # Please also see the NOTICE and LICENSE files for our notice and the LGPL.
  #
  # This program is free software; you can redistribute it and/or modify
  # it under the terms of the GNU Lesser General Public License (as
  # published by the Free Software Foundation) version 2.1, February 1999.
  #
  # 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 terms and
  # conditions of the GNU Lesser General Public License for more details.
  #
  # You should have received a copy of the GNU Lesser General Public
  # License along with this program; if not, write to the Free Software
  # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  ##############################################################################
  from spack import *
  
  
  class Libunwind(AutotoolsPackage):
      """A portable and efficient C programming interface (API) to determine
         the call-chain of a program."""
  
      homepage = "http://www.nongnu.org/libunwind/"
      url      = "http://download.savannah.gnu.org/releases/libunwind/libunwind-1.1.tar.gz"
  
      version('1.3-rc1', 'f09b670de5db6430a3de666e6aed60e3')
      version('1.2.1', '06ba9e60d92fd6f55cd9dadb084df19e', preferred=True)
      version('1.1', 'fb4ea2f6fbbe45bf032cd36e586883ce')
  
      variant('xz', default=False,
              description='Support xz (lzma) compressed symbol tables.')
  
      depends_on('xz', type='link', when='+xz')
  
      conflicts('platform=darwin',
                msg='Non-GNU libunwind needs ELF libraries Darwin does not have')
  
      provides('unwind')
  
      def configure_args(self):
          spec = self.spec
          args = []
  
          if '+xz' in spec:
              args.append('--enable-minidebuginfo')
          else:
              args.append('--disable-minidebuginfo')
  
          return args
  
subject: add version 1.3-rc1 and variant xz (#8989)