Instead of using the 'temp' and 'tempdir' DSL directives to create
temporary files, use fixed paths relative to __STATEDIR__.  This has two
advantages:
  1) The files are automatically cleaned up if the tests fail (and even if
     that doesn't work they're easier to clean up manuall)
  2) When debugging tests it's easier to figure out which of the temporary
     files are relevant to whatever's going wrong

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

The test scripts support a "req" directive which requires one test script
to be run before another.  It's implemented by doing a topological sort
based on these directives in the runner scripts, which is about as awkward
as you'd expect in Bourne shell.

It turns out we only use this functionality in one place - to make the
"make install" test run after the plain "make" test.  We also already have
a simpler way of making sure tests run in a specific order: just put them
into the same test script file.

So, remove support for the "req" directive and just fold the build/all and
build/install test scripts together.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

Build-time selection of AVX2 flags and routines is not practical for
distributions, but limiting AVX2 usage to checksum routines with
specific run-time detection doesn't allow for easy performance gains
from auto-vectorisation of batched packet handling routines.

For x86_64, build non-AVX2 and AVX2 binaries, and implement a simple
wrapper replacing the current executable with the AVX2 build if it's
available, and if AVX2 is supported by the current CPU.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

Not really quick, definitely dirty.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>