Buildcache: bindist test without invoking spack compiler wrappers. (#15687)

* Buildcache:
   * Try mocking an install of quux, corge and garply using prebuilt binaries
   * Put patchelf install after ccache restore
   * Add script to install patchelf from source so it can be used on Ubuntu:Trusty which does not have a patchelf pat package. The script will skip building on macOS
   * Remove mirror at end of bindist test
   * Add patchelf to Ubuntu build env
   * Revert mock patchelf package to allow other tests to run.
   * Remove depends_on('patchelf', type='build') relying instead on
   * Test fixture to ensure patchelf is available.

* Call g++ command to build libraries directly during test build

* Flake8

* Install patchelf in before_install stage using apt unless on Trusty where a build is done.

* Add some symbolic links between packages

* Flake8

* Flake8:

* Update mock packages to write their own source files

* Create the stage because spec search does not create it any longer

* updates after change of list command arguments

* cleanup after merge

* flake8

1 files changed, 10 insertions, 9 deletions

diff --git a/var/spack/repos/builtin.mock/packages/patchelf/package.py b/var/spack/repos/builtin.mock/packages/patchelf/package.py
index 0f72271921..80221e10e8 100644
--- a/var/spack/repos/builtin.mock/packages/patchelf/package.py
+++ b/var/spack/repos/builtin.mock/packages/patchelf/package.py
@@ -7,16 +7,17 @@ from spack import *
 
 
 class Patchelf(AutotoolsPackage):
-    """
-    PatchELF is a small utility to modify the
-    dynamic linker and RPATH of ELF executables.
-    """
+    """PatchELF is a small utility to modify the dynamic linker and RPATH of
+       ELF executables."""
 
     homepage = "https://nixos.org/patchelf.html"
-    url = "http://nixos.org/releases/patchelf/patchelf-0.8/patchelf-0.8.tar.gz"
-
-    list_url = "http://nixos.org/releases/patchelf/"
+    url      = "https://nixos.org/releases/patchelf/patchelf-0.10/patchelf-0.10.tar.gz"
+    list_url = "https://nixos.org/releases/patchelf/"
     list_depth = 1
 
-    version('0.9', '3c265508526760f233620f35d79c79fc')
-    version('0.8', '407b229e6a681ffb0e2cdd5915cb2d01')
+    version('0.10', sha256='b2deabce05c34ce98558c0efb965f209de592197b2c88e930298d740ead09019')
+    version('0.9',  sha256='f2aa40a6148cb3b0ca807a1bf836b081793e55ec9e5540a5356d800132be7e0a')
+    version('0.8',  sha256='14af06a2da688d577d64ff8dac065bb8903bbffbe01d30c62df7af9bf4ce72fe')
+
+    def install(self, spec, prefix):
+        install_tree(self.stage.source_path, prefix)