Example program for dggsvd

This example finds the generalized singular value decomposition
A = U Σ1 0R QT ,   B = V Σ2 0R QT ,  
where
A = 1 2 3 3 2 1 4 5 6 7 8 8   and   B = -2 -3 3 4 6 5 ,  
together with estimates for the condition number of R and the error bound for the computed generalized singular values.
The example program assumes that mn, and would need slight modification if this is not the case.