Freeze the versions of cabal-testsuite and solver-benchmarks

Validate rearrangements

Which are the extremes of support window at the moment.

This makes e.g. LibV09 test work properly

This is very useful for validate.sh script,
We should be aware of which tests are skipped.
Perfectly, SKIP should tell a reason.

regex-tdfa-1.3.1.0

Travis ghc 8.8

Use cabal-install-3.0, as otherwise we won't be able to build
custom setup for GHC-8.8

Use hackage-security-0.6

Also in CI setup, install hackage-repo-tool using `cabal new-install`.
And remove slightly confusing cabal.project.travis file.

Add test for #6083, build-depends: pkg:pkg

I'm adding this test, so we dont' silently change the behaviour
for `cabal-version: 3.0`

fetchRepoTarball output is non-deterministic

Limit version number parts to be 9 digits

Fix #5846, space after multilib

Fix #4130: Create incoming directory

Remove Slack notifications

This could solve some non-determinism in output of cabal-testsuite
which we experienced. There's sometimes spurious

    Downloading  pkgname-foo

In test outputs, which goes away when you restart the travis build

Add GHC-8.8 flags to normaliseGhcFlags (with test)

Pr/fix asm sources

This is OK to include in 3.0 release, as I consider this a bug
in initial release. We don't yet need to do heavy lifting as with mixins.

It's probably silent assumption that `setup Cabal.copyCommand`
would create directory structure. Who said it would do that.
For empty packages, sometimes it doesn't.

It's easier to be defensive here

Herbert Valerio Riedel authored 5 years ago and Oleg Grenrus committed 5 years ago

While those buildinfo fields were added to the parser some time
ago via 57d7f28e and
4a287659 that work was never completed
by implementing the necessary build/sdist logic in Cabal.

This commit remedies this oversight by implementing and wiring up the
missing build logic.

*WARNING* this commit is still very WIP; ASM works mostly; C--
          support is still incomplete

Fix typos

Second try to use zinza

Distribution.Compat.Async

validate.sh: Allow using short-version ghc binaries, like ghc-8.6

.travis.yml: Add fast_finish to get build status faster

Makefile rule to build Cabal with GHC-7.6