bug#54752: import: hackage: `elif` conditionals not supported

[Lars-Dominik Braun]

Hi Philip,

> Since Cabal 2.2 conditional blocks support the `elif` construct [0], but our 
> hackage importer does not currently support such expressions. This causes 
> importing packages like `raaz` [1] to fail.
attached patch series fixes the import for `raaz` by adding support for
elif and other minor adjustments. There still is syntax we do not support,
most importantly mixed indentation, which is already documented as xfail
via a testcase. I’m adding a few more.

Could you have a look please if these make sense?

Cheers,
Lars

0001-import-cabal-Support-elif-statement.patch
Description: Text document

0002-import-cabal-Allow-curly-brackets-in-more-positions.patch
Description: Text document

0003-import-cabal-Allow-properties-without-space-between-.patch
Description: Text document

0004-import-cabal-Allow-curly-bracket-before-else-stateme.patch
Description: Text document

0005-import-cabal-Document-failing-syntax-through-tests.patch
Description: Text document