Epetra #480 setup for the LAPACK testing of the dggsvd3 and sggsvd3.
Created by: MicheldeMessieres
Adds configure time check for dggsvd3 through CheckHaveLapackGSSVD3.cmake. Then defines HAVE_LAPACK_GSSVD3 which adds the new parameter LWORK to dggsvd3 and sggsvd3.
This was tested on LAPACK 3.6.0.
To resolve issue #480 (closed).