cabal-install-1.18 on GHC-6.12

[Henning Thielemann]

I am trying  to compile cabal-install-1.18.0.2 on GHC-6.12.1. It aborts 
with:

...
[12 of 73] Compiling Distribution.Client.Compat.Semaphore ( 
Distribution/Client/Compat/Semaphore.hs, 
dist/build/cabal/cabal-tmp/Distribution/Client/Compat/Semaphore.o )

Distribution/Client/Compat/Semaphore.hs:12:26:
     Module `Control.Exception' does not export `mask_'


That is, you must either narrow the dependency on 'base' or avoid 'mask_'.