package description fields

[Ross Paterson]

Proposals:

1) New field extra-tmp-files, a list of extra files to be removed by
   setup clean, beyond those that can be deduced.

2) Rename other-files as extra-source-files for consistency and clarity.

3) New field data-files, a list of files to be copied to a place where
   an executable can find them (e.g. template-hsc.h for hsc2hs):
	Hugs: the directory containing the Main module
	GHC/Windows: the directory containing the executable
	GHC/Unix: /usr/local/share/<exename>
   plus a new function in System.Directory to return the name of this
   directory.  That would address Dimitry's requirements in

	http://www.haskell.org/pipermail/haskell-cafe/2005-July/010886.html

   Dimitry has a more elaborate proposal:

	http://www.haskell.org/pipermail/libraries/2005-July/004146.html