Add appropriate include to pick up strerror_r.
We were getting lucky before, with lax compilers that happened to include cstring for us. This fixes a compile error on g++ 4.3. Thanks to Tom Evans (ORNL) for the report + fix. (This is a merge of 5612 from the RC.) git-svn-id: http://visit.ilight.com/svn/visit/trunk/src@5614 18c085ea-50e0-402c-830e-de6fd14e8384