Problem with SHGetFolderPath using Cabal on Windows 98

[Toby Allsopp]

When trying to use Cabal (e.g. running `runghc Setup.lhs' for HSQL or
running `ghci -package Cabal') on Windows 98, I get an error like the
following:

C:/GHC/GHC-6.4.1/HSCabal.o: unknown symbol `_SHGetFolderPathA'

This happens with GHC 6.4 and
ghc-6.4.1.20050803-i386-unknown-mingw32.tar.gz.

I believe that the problem is that the SHGetFolderPath function is not
included in SHELL32.DLL in Windows 98.  If the appropriate updates are
installed (new IE, I think) then it is available in SHFOLDER.DLL.  It
is also available in SHFOLDER.DLL in later versions of Windows.

I also believe, but haven't been able to verify, that #includeing
<shfolder.h> before using SHGetFolderPath will fix it.  I guess
changing something in libraries/Cabal/Distribution/Simple/Configure.hs
will do the trick, but I don't know much about the FFI.

Cheers,
Toby.