External packages do not have an spec.yaml file so don't check for it.
Without this change any time a package depends on an external package
when the new package is installed you will get the error

Install prefix exists but contains no spec.yaml

This problem has also haunted me since I started using Spack since PETSc
depends on Python and I used an external python but fortunately it
was relatively easy to debug once I could reproduce it at will.

Funded-by: IDEAS
Project: IDEAS/xSDK
Time: 1 hour

Fixes #1845

This replaces a custom token-based substitution format with calls to
Spec.format in modules.py

This also resolves a couple issues:

- LmodModules set configuration globally instead of in its initializer
  which meant test-specific configuration was not applied
- Added support for setting hash_length=0 for LmodModules. This only
  affects the module filename and not the directory names for the
  hierarchy tokens in the path. This includes an additional unit test.

* Made some refactoring improvements to the 'visit' and 'vtk' packages.

* Added a small fix for the 'vtk' package when building with 'qt+webkit'.

Funded-by: IDEAS
Project: IDEAS/xSDK
Time:  2 hours

The breaks `spack create`.

Removed documentation on false paths as per #2083

* document recommended usage of system blas/lapack

* update doc

* minor

* reword

Add the latest release of libSplash, version 1.5.0.

* spack install : added --log-format option (incorporates test-install command)

fixes #1907

* qa : removed extra whitespace

* openmpi: require fortran for now

* mpich: requre fortran for now

* mvapich2: require fortran for now

* openmpi: flake8 fixes

* Update the krell institute products to use the latest features of spack for building on cluster platforms.

* Address travis error messages and resubmit the pull request.

* Update the contents of openspeedshop package.py so it passes the flake8 tests.

* Fix flake8 error-whitespack issue in mrnet package.py file.

* Add updates based on spack reviewer feedback.

* More fixes based on comments from reviewers.  Switch using extend to using append, remove additional setting of PATH and LD_LIBRARY_PATH that should not be required due to RPATH.

* More review related changes.  Update MPIOption.append lines and take out xercesc references.

* Create a base options function for common openspeedshop base cmake options to reduce redundencies.

* Add libxml2+python depends on to get around issues with the libxml2 package file.

* veclibfort: add new package

* veclibfort: add a small test

Add a package for ant, a java build tool.

Add a package that installed the pre-built maven distribution.

I've given up, for now, on building maven from source.  That processed
stumbled on two points before I gave up:

1. It downloaded several hundred .{pop,jar} files and I despaired of
   figuring out some way of mirroring and checksumming them; and

2. It exploded complaining about too many unacceptable license files,
   which seems odd in its own source tree.

Perhaps someone with more Java fu that I admit to can figure it out.
In the meantime, this is useful.

* add filter_system_paths()

* filter system paths in set_build_environment_variables()

* two function: lib/inc + bin

* reverse order in bin

* fix order

* minor

* improvements of the code

* more cleanup

* alternative solution for filter_bins

* fiddle base alalazo's approach

* minor

* minor

Funded-by: IDEAS
Project: IDEAS/xSDK
Time: 1 hour

* libsodium: add latest versions, fix old versions

older versions of libsodium were added to an "old" subdirectory

* zeromq: add 4.1.4

prerequiste for the latest develop version of flux

Pkg-config depends on glib which depends on pkg-config. As a result,
pkg-config used to build glib internally. However, this fails on Mac.
Building pkg-config with an internal glib is now a variant, turned on
by default, and required to build glib.

* Add patch allowing GCC 6 to compile GCC 5

* Expand patch version range

* Tells boost explictly about libraries and headers

Ideally, bjam would determine the libraries and headers from the
executable. But it doesn't. This rigs a best guess for python libraries
and headers.

* Move glob import to top of file

* variable name change: alllibs --> all_libs

* Use dso suffix rather than hard-coded string

* Use only MAJOR.MINOR when setting up python in bjam

do_install : allow for an arbitrary number of phases

* Fixed a bug causing config-specified compiler flags to be ignored.
Updated the compiler config so all flags are in a separate section.

* Updated the documentation for the `compilers.yaml` file spec.

* Implemented basic testing for the 'flags' section of compiler config.

* Fixed a few minor problems with the manual compiler config documentation.

Funded-by: IDEAS
Project: IDEAS/xSDK
Time: .4 hours

* Adds new versions to eigen

* Reorder versions from oldest to newest