##############################################################################
# Copyright (c) 2013-2017, 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 GlobusToolkit(AutotoolsPackage):
    """The Globus Toolkit is an open source software toolkit used for building
       grids"""

    homepage = "http://toolkit.globus.org"
    url      = "http://toolkit.globus.org/ftppub/gt6/installers/src/globus_toolkit-6.0.1506371041.tar.gz"

    version('6.0.1506371041', 'e17146f68e03b3482aaea3874d4087a5')

var/spack/repos/builtin/packages/globus-toolkit/package.py
##############################################################################
# Copyright (c) 2013-2017, 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 GlobusToolkit(AutotoolsPackage):
    """The Globus Toolkit is an open source software toolkit used for building
       grids"""

    homepage = "http://toolkit.globus.org"
    url      = "http://toolkit.globus.org/ftppub/gt6/installers/src/globus_toolkit-6.0.1506371041.tar.gz"

    version('6.0.1506371041', 'e17146f68e03b3482aaea3874d4087a5')
    version('6.0.1493989444', '9e9298b61d045e65732e12c9727ceaa8')

    depends_on('openssl')

var/spack/repos/builtin/packages/globus-toolkit/package.py
diff --git a/var/spack/repos/builtin/packages/globus-toolkit/package.py b/var/spack/repos/builtin/packages/globus-toolkit/package.py
index eb24a1720889ef..8ad63395c665e0 100644
--- a/var/spack/repos/builtin/packages/globus-toolkit/package.py
+++ b/var/spack/repos/builtin/packages/globus-toolkit/package.py
@@ -33,3 +33,6 @@ class GlobusToolkit(AutotoolsPackage):
     url      = "http://toolkit.globus.org/ftppub/gt6/installers/src/globus_toolkit-6.0.1506371041.tar.gz"
 
     version('6.0.1506371041', 'e17146f68e03b3482aaea3874d4087a5')
+    version('6.0.1493989444', '9e9298b61d045e65732e12c9727ceaa8')
+
+    depends_on('openssl')

spack find : always prompt 0 installed packages
On a clean `develop` checkout : 

```
$ git clone https://github.com/LLNL/spack.git
Cloning into 'spack'...
remote: Counting objects: 25613, done.
remote: Compressing objects: 100% (42/42), done.
remote: Total 25613 (delta 12), reused 3 (delta 3), pack-reused 25557
Receiving objects: 100% (25613/25613), 6.65 MiB | 6.46 MiB/s, done.
Resolving deltas: 100% (13031/13031), done.
Checking connectivity... done.

$ cd spack
$ . share/spack/setup-env.sh 
$ spack compilers
==> Available compilers
-- gcc ----------------------------------------------------------
gcc@4.8

$ spack install zlib
==> Installing zlib
==> Trying to fetch from file:///home/mculpo/production/spack-mirror/zlib/zlib-1.2.8.tar.gz
######################################################################## 100,0%
==> Staging archive: /home/mculpo/tmp/spack/var/spack/stage/zlib-1.2.8-d6pdl6xvnvap6ihrqcqtgvweghbszmix/zlib-1.2.8.tar.gz
==> Created stage in /home/mculpo/tmp/spack/var/spack/stage/zlib-1.2.8-d6pdl6xvnvap6ihrqcqtgvweghbszmix
==> No patches needed for zlib
==> Building zlib
==> Successfully installed zlib
  Fetch: 0.01s.  Build: 3.69s.  Total: 3.70s.
[+] /home/mculpo/tmp/spack/opt/spack/linux-x86_64/gcc-4.8/zlib-1.2.8-d6pdl6xvnvap6ihrqcqtgvweghbszmix

$ spack find
==> 0 installed packages.

$ spack install szip
==> Installing szip
==> Trying to fetch from file:///home/mculpo/production/spack-mirror/szip/szip-2.1.tar.gz
######################################################################## 100,0%
==> Staging archive: /home/mculpo/tmp/spack/var/spack/stage/szip-2.1-esfmhl54wbdb7nnnip6y6jbxlbmxs2jq/szip-2.1.tar.gz
==> Created stage in /home/mculpo/tmp/spack/var/spack/stage/szip-2.1-esfmhl54wbdb7nnnip6y6jbxlbmxs2jq
==> No patches needed for szip
==> Building szip
==> Successfully installed szip
  Fetch: 0.01s.  Build: 8.09s.  Total: 8.10s.
[+] /home/mculpo/tmp/spack/opt/spack/linux-x86_64/gcc-4.8/szip-2.1-esfmhl54wbdb7nnnip6y6jbxlbmxs2jq

$ spack find 
==> 0 installed packages.
```

The db seems to be written correctly : 

```
database:
  installs:
    d6pdl6xvnvap6ihrqcqtgvweghbszmix:
      explicit: true
      installed: true
      path: /home/mculpo/tmp/spack/opt/spack/linux-x86_64/gcc-4.8/zlib-1.2.8-d6pdl6xvnvap6ihrqcqtgvweghbszmix
      ref_count: 0
      spec:
        zlib:
          arch: linux-x86_64
          compiler:
            name: gcc
            version: '4.8'
          dependencies: {}
          namespace: builtin
          parameters:
            cflags: []
            cppflags: []
            cxxflags: []
            fflags: []
            ldflags: []
            ldlibs: []
          version: 1.2.8
    esfmhl54wbdb7nnnip6y6jbxlbmxs2jq:
      explicit: true
      installed: true
      path: /home/mculpo/tmp/spack/opt/spack/linux-x86_64/gcc-4.8/szip-2.1-esfmhl54wbdb7nnnip6y6jbxlbmxs2jq
      ref_count: 0
      spec:
        szip:
          arch: linux-x86_64
          compiler:
            name: gcc
            version: '4.8'
          dependencies: {}
          namespace: builtin
          parameters:
            cflags: []
            cppflags: []
            cxxflags: []
            fflags: []
            ldflags: []
            ldlibs: []
          version: '2.1'
  version: 0.9.1
```

xrootd requires zlib to be installed on system
CMake can't find zlib when installing xrootd. zlib is not listed as a dependency fro xrootd, so CMake looks for it on the system.
