Fix for Linux FieldWorks to run okay on the develop branch

Two relatively new items are preventing FieldWorks from running on
Linux: the new hunspell code is not quite right for Linux, and the new
message slice requires a chorus DLL which does not yet exist for Linux
in the FieldWorks context.  (See FWNX-1056.)  This fixes the hunspell
setup, and patches the message slice to not cause problems without a
chorus DLL.

Change-Id: I1ae4059b2ef731151bb7cffd6fb7f25491b79433