Bug relates to the interplay between:
1. random dict orders in python 3.5
2. bugfix in initial implementation of stacks for `_concretize_dependencies`
   when `self._dependencies` is empty
3. bug in coconcretization algorithm computation of split specs

Result was transient hang in coconcretization.
Fixed #3 (bug in coconcretization) to resolve.

* Fixed building coreutils on Darwin

* Bump nano version to 4.9

* Coreutils: Add program prefix g so we don't conflict with Apple utilities

* Fix intendation

* Make format more spack like

* Removed unnecesary changes

* Merge branch 'develop' of github.com:DiegoMagdaleno/spack into develop

Fix linking libgit2 on Darwin

* Revert "Merge pull request #3 from spack/develop"

This reverts commit 58dbbdb, reversing
changes made to dd7a413.

* Revert "Revert "Merge pull request #3 from spack/develop""

This reverts commit f956aa7.

* Revert "Merge branch 'develop' of github.com:DiegoMagdaleno/spack into develop"

This reverts commit 50321f7.

Whenever attempting to use any ncurses functionality within cscope, a
page fault would result within the ncurses library.

    Program received signal SIGSEGV, Segmentation fault.
    0x00007ffff7fad3cf in termattrs_sp () from .../lib/libncursesw.so.6
    (gdb) bt
    #0  0x00007ffff7fad3cf in termattrs_sp () from .../lib/libncursesw.so.6
    #1  0x00007ffff7faa794 in _nc_setupscreen_sp () from .../lib/libncursesw.so.6
    #2  0x00007ffff7fa614c in newterm_sp () from .../lib/libncursesw.so.6
    #3  0x00007ffff7fa65b9 in newterm () from .../lib/libncursesw.so.6
    #4  0x00007ffff7fa2970 in initscr () from .../lib/libncursesw.so.6
    #5  0x0000000000403dc2 in main (argc=<optimized out>, argv=0x7fffffffcea8) at main.c:574

This is due to a conflict between libtinfo.so and libtinfow.so. Both are
linked into cscope:

    $ ldd $(which cscope)
    /bin/bash: .../lib/libtinfo.so.6: no version information available (required by /bin/bash)
        linux-vdso.so.1 (0x00007fff5dbcb000)
        libncursesw.so.6 => .../lib/libncursesw.so.6 (0x00007f435cc69000)
        libtinfo.so.6 => .../lib/libtinfo.so.6 (0x00007f435cc2c000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f435ca29000)
        libtinfow.so.6 => .../lib/libtinfow.so.6 (0x00007f435c9e8000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f435cca7000)

Specifically linking libtinfow.so instead of libtinfo.so resolves the
issue.

All instances of '...' above represent the path to the installed ncurses
for Spack.

* Add Collier and SysCalc recipes

* Remove extra syscalc version

* Build collier with -j1 for @:1.2.4

* Add recipe for gosam-contrib

* Update gosam-contrib recipe with 'provides'

* Madgraph recipe, first version

* Finalize madgraph recipe + flake8

* Make py2 version of madgraph default; fix hash for syscalc; fix patch

* Handle virtual packages (#3)

* Update package.py

* Update packages.yaml

* Remove virtual packages - pt. 1

* Remove virtual packages - pt. 2

* Changes from review - pt. 1

* Changes from code review - pt. 2

* Update var/spack/repos/builtin/packages/collier/package.py

Co-authored-by: Adam J. Stewart <[email protected]>

* Update var/spack/repos/builtin/packages/madgraph5amc/package.py

Co-authored-by: Adam J. Stewart <[email protected]>

* Add hash for version 2.7.2 (available in our private mirror)

* Fixes for 2.7.3 family

* Patches for 2.7.3{.py3,}{.atlas,}

* Fix hash of syscalc

* Hack to fix concretization (2.7.3 matches 2.7.3.py3)

* Add conflict statement (reported to devs)

* Apply suggestions from code review

Co-authored-by: Adam J. Stewart <[email protected]>

* Update package.py

* Delete madgraph5amc-2.7.2.atlas.patch

* Delete madgraph5amc-2.7.2.patch

* Update package.py

* Apply suggestions from code review

Co-authored-by: Adam J. Stewart <[email protected]>

Co-authored-by: iarspider <[email protected]>
Co-authored-by: Adam J. Stewart <[email protected]>