Unreliability of the build system

[Jan Stolarek]

> The haddock failure you're seeing is caused by using relative symlinks
> with lndir. See #7879.
Thanks, that's one problem less :) I applied the patch and I'm running the validation to see if 
that works.

> Perhaps you have different library versions checked out in
> different trees; you could check whether or not this is the case by
> looking at the various trees' fingerprints.
According to fingerprints the trees are identical. I diffed both directories and there are some 
minor differences, but I think these come from the fact that ghc-working never contained build 
artifacts, whereas ghc-validate was cleaned with 'make maintainer-clean', which might have been 
inaccurate.

> Personally, I think the current mix of git submodules and non-git
> submodule dependencies is horrible. It makes it impossible to check out
> a consistent tree without a full fingerprint while also incurring all
> the disadvantages of submodules.
I admit I don't understand motivation for using both git submodules and non-git submodules.

What worries me the most is unreliability of the test suite. After getting 200 test failures 
mentioned in the previous mail, I ran the validation again and got only 3 failures. I ran one of 
the failed tests manually and it passed, leaving me with two known failures.

Janek