GitLab

the layout changed in the new GHC build system

rather than low-level System.Posix.Internals operations which are
about to go away.

It was getting increasingly convoluted and incomprehensible.
Now uses the Program.HcPkg and Program.Scripts modules.

More flexible and based on the ProgramInvocation stuff

For tasks like registering where we call hc-pkg, this allows us to
produce a single program invocation and then either run it directly
or write it out as a script.

Close the input after pushing it. Return any error message.

Add an explicit intermediate ProgramInvocation data type.

It is a bad idea for clean to do anything different depending
on whether the package was configured already or not. The
actual cleaning code did not use the LocalBuildInfo so this
only changes in the UserHooks interface. No Setup.hs scripts
actually make of this parameter for the clean hook.
Part of ticket #133.

Since we now always have a GenericPackageDescription

Rather than Either GenericPackageDescription PackageDescription
In principle this is an interface change that could break Setup.hs
scripts but in practise the few scripts that use confHook just pass
the arguments through and so are not sensitve to the type change.

Also changes Simple.defaultMainNoRead to use GenericPackageDescription.
This is an API change that in principle could break Setup.hs scripts
but in practise there are no Setup.hs scripts that use either.

The arguments to isPrefixOf were the wrong way round. We want to see if
the line starts "\\begin{code}", not if the line is a prefix of that string.