New, cleaner package repository structure.

Package repositories now look like this:

    top-level-dir/
        repo.yaml
        packages/
            libelf/
                package.py
            mpich/
                package.py
            ...

This leaves room at the top level for additional metadata, source,
per-repo configs, indexes, etc., and it makes it easy to see that
something is a spack repo (just look for repo.yaml and packages).

var/spack/repos/builtin/packages/libdwarf/package.py

@@ -0,0 +1,81 @@
+##############################################################################
+# 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://scalability-llnl.github.io/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 import *
+import os
+
+# Only build certain parts of dwarf because the other ones break.
+dwarf_dirs = ['libdwarf', 'dwarfdump2']
+
+class Libdwarf(Package):
+    """The DWARF Debugging Information Format is of interest to
+       programmers working on compilers and debuggers (and any one
+       interested in reading or writing DWARF information). It was
+       developed by a committee (known as the PLSIG at the time)
+       starting around 1991. Starting around 1991 SGI developed the
+       libdwarf and dwarfdump tools for internal use and as part of
+       SGI IRIX developer tools. Since that time dwarfdump and
+       libdwarf have been shipped (as an executable and archive
+       respectively, not source) with every release of the SGI
+       MIPS/IRIX C compiler."""
+
+    homepage = "http://www.prevanders.net/dwarf.html"
+    url      = "http://www.prevanders.net/libdwarf-20130729.tar.gz"
+    list_url = homepage
+
+    version('20130729', '4cc5e48693f7b93b7aa0261e63c0e21d')
+    version('20130207', '64b42692e947d5180e162e46c689dfbf')
+    version('20130126', 'ded74a5e90edb5a12aac3c29d260c5db')
+
+    depends_on("libelf")
+
+    parallel = False
+
+
+    def install(self, spec, prefix):
+        # dwarf build does not set arguments for ar properly
+        make.add_default_arg('ARFLAGS=rcs')
+
+        # Dwarf doesn't provide an install, so we have to do it.
+        mkdirp(prefix.bin, prefix.include, prefix.lib, prefix.man1)
+
+        with working_dir('libdwarf'):
+            configure("--prefix=" + prefix, "--enable-shared")
+            make()
+
+            install('libdwarf.a',  prefix.lib)
+            install('libdwarf.so', prefix.lib)
+            install('libdwarf.h',  prefix.include)
+            install('dwarf.h',     prefix.include)
+
+        with working_dir('dwarfdump2'):
+            configure("--prefix=" + prefix)
+
+            # This makefile has strings of copy commands that
+            # cause a race in parallel
+            make(parallel=False)
+
+            install('dwarfdump',      prefix.bin)
+            install('dwarfdump.conf', prefix.lib)
+            install('dwarfdump.1',    prefix.man1)