old_contents: ##############################################################################
  # Copyright (c) 2013, Lawrence Livermore National Security, LLC.
  # Produced at the Lawrence Livermore National Laboratory.
  #
  # This file is part of Spack.
  # Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
  # LLNL-CODE-647188
  #
  # For details, see https://github.com/llnl/spack
  # Please also see the LICENSE file 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 General Public License (as published by
  # the Free Software Foundation) version 2.1 dated 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 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.compiler import *
  
  class Clang(Compiler):
      # Subclasses use possible names of C compiler
      cc_names = ['clang']
  
      # Subclasses use possible names of C++ compiler
      cxx_names = ['clang++']
  
      # Subclasses use possible names of Fortran 77 compiler
      f77_names = []
  
      # Subclasses use possible names of Fortran 90 compiler
      fc_names = []
  
      # Named wrapper links within spack.build_env_path
      link_paths = { 'cc'  : 'clang/clang',
                     'cxx' : 'clang/clang++',
                     # Use default wrappers for fortran, in case provided in compilers.yaml
                     'f77' : 'f77',
                     'fc'  : 'f90' }
  
      @classmethod
      def default_version(self, comp):
          """The '--version' option works for clang compilers.
             Output looks like this::
  
                 clang version 3.1 (trunk 149096)
                 Target: x86_64-unknown-linux-gnu
                 Thread model: posix
          """
          return get_compiler_version(
              comp, '--version', r'(?:clang version|based on LLVM) ([^ )]+)')
  
new_contents: ##############################################################################
  # Copyright (c) 2013, Lawrence Livermore National Security, LLC.
  # Produced at the Lawrence Livermore National Laboratory.
  #
  # This file is part of Spack.
  # Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
  # LLNL-CODE-647188
  #
  # For details, see https://github.com/llnl/spack
  # Please also see the LICENSE file 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 General Public License (as published by
  # the Free Software Foundation) version 2.1 dated 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 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.compiler import *
  
  class Clang(Compiler):
      # Subclasses use possible names of C compiler
      cc_names = ['clang']
  
      # Subclasses use possible names of C++ compiler
      cxx_names = ['clang++']
  
      # Subclasses use possible names of Fortran 77 compiler
      f77_names = []
  
      # Subclasses use possible names of Fortran 90 compiler
      fc_names = []
  
      # Named wrapper links within spack.build_env_path
      link_paths = { 'cc'  : 'clang/clang',
                     'cxx' : 'clang/clang++',
                     # Use default wrappers for fortran, in case provided in compilers.yaml
                     'f77' : 'f77',
                     'fc'  : 'f90' }
  
      @classmethod
      def default_version(self, comp):
          """The '--version' option works for clang compilers.
             Output looks like this::
  
                 clang version 3.1 (trunk 149096)
                 Target: x86_64-unknown-linux-gnu
                 Thread model: posix
          """
          return get_compiler_version(
              comp, '--version', r'(?:clang version|based on LLVM|LLVM version) ([^ )]+)')
  
subject: Fix regex to find version on OS X