Fix ifdef logic so it works for GCC.
Fix ifdef logic so it works for GCC.

Refs #2281.

capitalaslash/libmesh,BalticPinguin/libmesh,BalticPinguin/libmesh,roystgnr/libmesh,dschwen/libmesh,roystgnr/libmesh,libMesh/libmesh,dschwen/libmesh,dschwen/libmesh,capitalaslash/libmesh,jwpeterson/libmesh,jwpeterson/libmesh,jwpeterson/libmesh,jwpeterson/libmesh,jwpeterson/libmesh,roystgnr/libmesh,capitalaslash/libmesh,roystgnr/libmesh,jwpeterson/libmesh,dschwen/libmesh,BalticPinguin/libmesh,dschwen/libmesh,roystgnr/libmesh,libMesh/libmesh,capitalaslash/libmesh,jwpeterson/libmesh,roystgnr/libmesh,libMesh/libmesh,dschwen/libmesh,libMesh/libmesh,jwpeterson/libmesh,dschwen/libmesh,capitalaslash/libmesh,capitalaslash/libmesh,libMesh/libmesh,roystgnr/libmesh,capitalaslash/libmesh,capitalaslash/libmesh,BalticPinguin/libmesh,libMesh/libmesh,BalticPinguin/libmesh,roystgnr/libmesh,libMesh/libmesh,BalticPinguin/libmesh,dschwen/libmesh,BalticPinguin/libmesh,BalticPinguin/libmesh,libMesh/libmesh