patch applied (packages/base): Fix bugs regarding asynchronous exceptions and laziness in Control.Concurrent.SampleVar

[Simon Marlow]

Thu Mar 18 13:01:04 PDT 2010  Bas van Dijk <v.dijk.bas at gmail.com>
  * Fix bugs regarding asynchronous exceptions and laziness in Control.Concurrent.SampleVar
   - Block asynchronous exceptions at the right places
   - Force thunks before putting them in a MVar

    M ./Control/Concurrent/SampleVar.hs -13 +17