Needed for POSIX compliance for text files

- Fix whitespace in cabal-testsuite + other tests

Support GHC2024 (fixes #9736)

* Add tests for #9742

`main-is` not picked up when inside a multibranch CondNode.

* Fix comments

* Add simplifyBranch to Distribution.Types.CondTree

Goes hand in hand with with simplifyCondTree.

* Make `check` deal correctly with multiple branches

`cabal check` had a problem recognising fields in presence of
multiple branches. This patch fixes the problem and does not
meaningfully increases CI time of particularly taxing tests
(like “duplicate flagged dependencies” from MemoryUsage).

---------

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Testsuite: pass -i argument to runghc invocations

This commit modifies the generation of runghc commands to pass an
additional -i argument to account for the change in working directory.

This ensures that, in the testsuite, runghc is able to see other modules.
For example, an invocation of runghc to run a Custom Setup script will
now properly see the modules imported, e.g. if one has a directory
structure like

  test.cabal
  Setup.hs
  SetupDep.hs

and Setup.hs imports SetupDep.hs.

offline flag disables `source-repository-package` sync

https://github.com/haskell/cabal/issues/9641

warning when offline mode skips `source-repository-package`s
i.e.
```
Warning: --offline was specified, skipping sync of repositories:
Warning: https://github.com/haskell/text.git
```

Remove skipIfGhcVersion "== 9.6.3"

Tell zlib not to use pkg-config

* Add GitLab CI badge

* whitespace fixup

I managed to mess things up using the UI editor.

---------

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Fix typo

Missing full stop.

Remove stale see 'withSourceCopyDir'

Update .cabal files

`extra-doc-files` and `no-autogen-paths` warnings.

Fix cabal install in the presence of extra-packages

Extra-packages listed in a cabal project are to be fetched from hackage,
and will be in memory as 'NamedPackages' rather than resolved to
'SpecificSourcePackage'.

On install, we need to make source-dists for all the specific source
packages, and fetch other packages from hackage. Since extra-packages
are already 'NamedPackages', we simply return them along the sdistize-d
specific source packages and the hackage source packages -- they will be
correctly fetched from Hackage from install.

Previously, cabal install <tgt> on a project with extra-packages would
fail because the branch of 'NamedPackage' for 'PackageSpecifier' was
simply unimplemented.

Fixes #8848

Find build-tool installed programs before programs in path

We must consider the path to the installed build-tool before the path to
existing versions of the build tool in paths such as `extra-prog-path`
or in the system path.

This was previously fixed by #8972 but undone by #9527.

This also renames `appendProgramSearchPath` to
`prependProgramSearchPath` to describe correctly what that function
does.

Fixes #9756

See: #4899

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Fix `<more complex packages>` link lost in doc/cabal-package-description-file.rs

Not able to reproduce the problem this avoids. Tested with;

- --with-cabal=./dist-newstyle/build/x86_64-linux/ghc-9.6.3/cabal-install-3.11.0.0/x/cabal/build/cabal/cabal
--with-cabal=./dist-newstyle/build/x86_64-linux/ghc-9.8.1/cabal-install-3.11.0.0/x/cabal/build/cabal/cabal

Add Issue/PR contributing guidelines

Regarding issues/PRs relationship.

Use in-tree Cabal library for `cabal-install` tests with custom setup.

The idea here is to pass a `--package-db` flag to `cabal-install` which
contains just `Cabal` and `Cabal-syntax` of the specific version. This
allows `cabal-install` tests to use the in-tree `Cabal` version,
something which you can easily run into and get very confused about when
writing tests.

There are a few options which can be passed to `cabal-tests` executable
to control which Cabal library you will test against.

1. --boot-cabal-lib specifies to use the Cabal library bundled with the
   test compiler, this is the default and existing behaviour of the
   testsuite.
2. --intree-cabal-lib=<root_dir> specifies to use Cabal and Cabal-syntax
   from a specific directory, and `--test-tmp` indicates where to put
   the package database they are built with.
3. --specific-cabal-lib=<VERSION> specifies to use a specific Cabal
   version from hackage (ie 3.10.2.0) and installs the package database
   into --test-tmp=<DIR>

The end result is that changes in the Cabal library can be tested with
cabal-install tests in the testsuite.

There have been a number of confusing issues with people writing tests
for changes in the Cabal library which never ran because of
cabal-install tests always used the boot Cabal library (see #9425
for one).

Fixes #9681

update copyright for 2024