* bugfix: make compiler preferences slightly saner

This fixes two issues with the way we currently select compilers.

If multiple compilers have the same "id" (os/arch/compiler/version), we
currently prefer them by picking this one with the most supported
languages.  This can have some surprising effects:

* If you have no `gfortran` but you have `gfortran-8`, you can detect
  `clang` that has no configured C compiler -- just `f77` and `f90`. This
  happens frequently on macOS with homebrew. The bug is due to some
  kludginess about the way we detect mixed `clang`/`gfortran`.

* We can prefer suffixed versions of compilers to non-suffixed versions,
  which means we may select `clang-gpu` over `clang` at LLNL. But,
  `clang-gpu` is not actually clang, and it can break builds. We should
  prefer `clang` if it's available.

- [x] prefer compilers that have C compilers and prefer no name variation
  to variation.

* tests: add test for which()

Apple's gcc is really clang. We previously ignored it by default but
there was a regression in #17110.

Originally we checked for all clang versions with this, but I know of
none other than `gcc` on macos that actually do this, so limiting to
`apple-clang` should be ok.

- [x] Fix check for `apple-clang` in `gcc.py` to use version detection
  from `spack.compilers.apple_clang`

Ensure compilers installed from buildcache are registered.

The `spack-build-env.txt` file may contains many secrets, but the obvious one is the private signing key in `SPACK_SIGNING_KEY`. This file is nonetheless uploaded as a build artifact to gitlab. For anyone running CI on a public version of Gitlab this is a major security problem. Even for private Gitlab instances it can be very problematic.

Co-authored-by: Scott Wittenburg <scott.wittenburg@kitware.com>

* llvm-flang Only build offload code if cuda enabled

The current version executes `cmake(*args)` always as part of the post install.  If device offload is not part of the build, this results in referencing `args` without it being set and the error:

```
==> Error: UnboundLocalError: local variable 'args' referenced before assignment

```

Looking at prevoous version of `llvm-package.py` this whole routine appears to be only required for offload, some indent `cmake/make/install` to be under the `if`.

* Update package.py

Add comment

* clear mpi env vars

The error message was not updated when the behavior of Spack environments
was changed to not automatically activate the local environment in #17258.
The previous error message no longer makes sense.

When Spack installs a package, it stores repository package.py files
for it and all of its dependencies - any package with a Spack metadata
directory in its installation prefix.

It turns out this was too broad: this ends up including external
packages installed by Spack (e.g. installed by another Spack instance).
Currently Spack doesn't store the namespace properly for such packages,
so even though the package file could be fetched from the external,
Spack is unable to locate it.

This commit avoids the issue by skipping any attempt to locate and copy
from the package repository of externals, regardless of whether they
have a Spack repo directory.

On Cray platforms, we rely heavily on the module system to figure out
what targets, compilers, etc. are available. This unfortunately means
that we shell out to the `module` command as part of platform
initialization.

Because we run subcommands in a shell, we can get infinite recursion if
`setup-env.sh` and friends are in some init script like `.bashrc`.

This fixes the infinite loop by adding guards around `setup-env.sh`,
`setup-env.csh`, and `setup-env.fish`, to prevent recursive
initializations of Spack. This is safe because Spack never shells out to
itself, so we do not need it to be initialized in subshells.

- [x] add recursion guard around `setup-env.sh`
- [x] add recursion guard around `setup-env.csh`
- [x] add recursion guard around `setup-env.fish`

* fix binutils deptype for gcc

binutils needs to be a run dependency of gcc

* Fix gcc+binutils build on RHEL7+

static-libstdc++ is not available with system gcc.
Anyway, as it is for bootstraping, we do not really care depending on
a shared libstdc++.

Co-authored-by: Michael Kuhn <michael@ikkoku.de>

Spack was attempting to calculate abspath on the located config.guess
path even when it was not found (None); this commit skips the abspath
calculation when config.guess is not found.

it's    mpi_compiler_wrappers
and not mpi_compiler._wrappers

fixes 2nd part of #17371

The previous fix from #17149 contained a thinko that produced errors for
packages that overwrite configure_directory.

* Activate environment in container file

This PR will ensure that the container recipes will build the spack
environment by first activating the environment.

* Deactivate environment before environment collection

For Singularity, the environment must be deactivated before running the
command to collect the environment variables. This is because the
environment collection uses `spack env activate`.

* Don't detect "classic" on Cray to avoid a compiler bug

* add tests

Co-authored-by: Gregory Becker <becker33@llnl.gov>

* share/spack/setup-env.fish file to setup environment in fish shell

* setup-env.fish testing script

* Update share/spack/setup-env.fish

Co-Authored-By: Elsa Gonsiorowski, PhD <gonsie@me.com>

* Update share/spack/qa/setup-env-test.fish

Co-Authored-By: Adam J. Stewart <ajstewart426@gmail.com>

* updates completions using `spack commands --update-completion`

* added stderr-nocaret warning

* added fish shell tests to CI system


Co-authored-by: becker33 <becker33@llnl.gov>
Co-authored-by: Adam J. Stewart <ajstewart426@gmail.com>
Co-authored-by: Elsa Gonsiorowski, PhD <gonsie@me.com>

* check link dirs for existence

Small fix so that immintrin.h gets included properly when the
compiler sets __F16C__. Upstream has been notified.

https://github.com/STEllAR-GROUP/hpx/issues/4728#issuecomment-640685308

Co-authored-by: Mark Olesen <Mark.Olesen@esi-group.com>

Added master branch, too

* [whizard] fix runtime compilers

fix

* [whizard] flake8

* [whizard] add master branch

* [py-mdanalysis] new version and added dependencies

Original commit message:

Author: Andrew Elble <aweits@rit.edu>
Date:   Thu Nov 14 08:35:14 2019 -0500

    mdanalysis

* [py-mdanalysis] python is type build/run

* [py-mdanalysis] updated numpy version requirement for all listed versions of py-mdanalysis

* [py-mdanalysis] updated biopython version requirement for all listed versions of py-mdanalysis

* [py-mdanalysis] updated py-griddataformats version requirement for all listed versions of py-mdanalysis

* [py-mdanalysis] gsd only required after version 1.17.0 and requires gsd@1.4.0

* [py-mdanalysis] only requires mmtf-python after version 0.16.0 and requires version 1.0.0

* [py-mdanalysis] has required py-joblib since version 0.16

* [py-mdanalysis] updated py-scipy version requirement for all listed versions of py-mdanalysis

* [py-mdanalysis] updated py-matplotlib version requirement for all listed versions of py-mdanalysis

* [py-mdanalysis] has required py-mock since version 0.18.0

* [py-mdanalysis] py-scikit-learn only required after version 0.16.0 and only for +analysis variant

* [py-mdanalysis] Reordered and reformatted for readability

* [py-mdanalysis] flake8 fixes

* [py-mdanalysis] proactively adding version 1.0.0 while I'm here since major release

* [py-mdanalysis] fixing some forgotten colons

* [py-crossmap] added version 0.3.9

* [py-crossmap] py-numpy not required

* [py-crossmap] py-cython must be >= 0.17

* [ruby] fixing path to gcc such that users can use gem to install native gems to their home directory

* [ruby] working on making flake8 happier

* [ruby] Line can't really be split cleanly. Enhancing flake8's calm.

ya learn something new every day...

* [ruby] line break where requested

* [ruby] make raw string

* [ruby] only running for x86_64-linux everything else is untested

* [ruby] finding rbconfig.rb in a cross platform manner

* new package: GraphBlast

* polish

* add cuda_arch setup

* flake8

* the package requires cuda variant and dependency

* add comments

* define cuda_arch

* implement multiple and custom cuda arches

* tidy up, improve

* flake8

* improve style

* add variant description

* use patch method, add new version for latest commit building since master now fails

* remove gcc conflict, tidy up

* also indicate build range for boost

Co-authored-by: Sinan81 <sbulut@3vgeomatics.com>
Co-authored-by: Sinan81 <Sinan81@github>

Renamed xspp to hspp

Co-authored-by: Sinan81 <sbulut@3vgeomatics.com>
Co-authored-by: Adam J. Stewart <ajstewart426@gmail.com>
Co-authored-by: Sinan81 <Sinan81@github>