Merge branch 'develop' into features/hwloc

* develop: (85 commits)
  Make libxcb compile with gcc 4.9.
  disable parallel install for glib (found races)
  disable cairo-trace, which is incompatible with older libiberty.h.
  Fix LaunchMon on newer gcc versions.
  Simplify output redirection in spack.util.executable
  Allow completely empty config files.
  Update cmake package to use http in all URLs.
  Fix create, diy, edit, and repo commands to use multiple repos.
  Add namespace option to find command.
  Temporary fix: Clang is the default compiler on Mac OS X.
  Netcdf requires cmake >=2.8.12
  Mbedtls depends on cmake
  Update libtool to 2.4.6
  Update Julia to 0.4.3
  Make binutils build on OS X
  Add verbs and psm variants
  py-matplotlib: depend on freetype
  py-numpy: make blas/lapack optional dependencies
  qhull: apply patch to work with libc++'s standard library
  New package GNU tar
  ...

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

@@ -0,0 +1,33 @@
+from spack import *
+
+class Hwloc(Package):
+    """The Portable Hardware Locality (hwloc) software package
+       provides a portable abstraction (across OS, versions,
+       architectures, ...) of the hierarchical topology of modern
+       architectures, including NUMA memory nodes, sockets, shared
+       caches, cores and simultaneous multithreading. It also gathers
+       various system attributes such as cache and memory information
+       as well as the locality of I/O devices such as network
+       interfaces, InfiniBand HCAs or GPUs. It primarily aims at
+       helping applications with gathering information about modern
+       computing hardware so as to exploit it accordingly and
+       efficiently."""
+    homepage = "http://www.open-mpi.org/projects/hwloc/"
+    url      = "http://www.open-mpi.org/software/hwloc/v1.9/downloads/hwloc-1.9.tar.gz"
+    list_url = "http://www.open-mpi.org/software/hwloc/"
+    list_depth = 3
+
+    version('1.11.2', '486169cbe111cdea57be12638828ebbf')
+    version('1.11.1', '002742efd3a8431f98d6315365a2b543')
+    version('1.9',    '1f9f9155682fe8946a97c08896109508')
+
+    depends_on('libpciaccess')
+
+    def url_for_version(self, version):
+        return "http://www.open-mpi.org/software/hwloc/v%s/downloads/hwloc-%s.tar.gz" % (version.up_to(2), version)
+
+    def install(self, spec, prefix):
+        configure("--prefix=%s" % prefix)
+
+        make()
+        make("install")