Merge pull request #6425 from phadej/backporting-to-3.0

.docker/validate-7.10.3.dockerfile

.docker/validate-7.6.3.dockerfile

.docker/validate-7.8.4.dockerfile

.docker/validate-8.0.2.dockerfile

.docker/validate-8.2.2.dockerfile

.docker/validate-8.4.4.dockerfile

.docker/validate-8.6.5.dockerfile

.docker/validate-8.8.1.dockerfile

.dockerignore

Cabal/Cabal.cabal

Cabal/ChangeLog.md

Cabal/Distribution/Compat/FilePath.hs

Cabal/Distribution/PackageDescription/Check.hs

Cabal/Distribution/Simple/Program/GHC.hs

Cabal/Distribution/Simple/Utils.hs

Cabal/tests/UnitTests/Distribution/Simple/Utils.hs

Makefile

cabal-testsuite/Test/Cabal/Monad.hs

cabal-testsuite/Test/Cabal/Prelude.hs

cabal-testsuite/main/cabal-tests.hs