ghc-pkg check problem in 6.10.2

[Simon Marlow]

I just noticed that the new 'ghc-pkg check' feature exposes a silly mistake 
in the definition of the rts package that we ship with GHC 6.10.2:

$ ghc-pkg check
There are problems in package rts-1.0:
   include-dirs: PAPI_INCLUDE_DIR doesn't exist or isn't a directory

...

To fix it, issue this command:

  $ ghc-pkg describe rts | sed 's/PAPI_INCLUDE_DIR//' | ghc-pkg update -

and now "ghc-pkg check" should give no errors:

  $ ghc-pkg check
  $

(Except on Windows, where there also seems to be a problem with the Haddock 
package.  Haddock itself is ok, but the Haddock library has some problems 
with its registration.)

Cheers,
	Simon