These patches handle API changes in process-1.1 and also remove usage of deprecated -XDatatypeContext for PipeCommand and EnvironCommand.
Removed usage of DatatypeContext for GHC 7.2
Defend against change in process API in 1.1
Added a flag to select version of process to use
I just learned about MIN_VERSION_ macros. This is MUCH simpler.
This addresses issue #4