Repository: spack/spack

Issue:
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.
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.
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
```



Discussion:

Resolving patch:
diff --git a/var/spack/repos/builtin/packages/xrootd/package.py b/var/spack/repos/builtin/packages/xrootd/package.py
--- a/var/spack/repos/builtin/packages/xrootd/package.py
+++ b/var/spack/repos/builtin/packages/xrootd/package.py
@@ -39,3 +39,4 @@ class Xrootd(CMakePackage):
     version('4.3.0', '39c2fab9f632f35e12ff607ccaf9e16c')
 
     depends_on('cmake@2.6:', type='build')
+    depends_on('zlib')


Test patch: