Openblas dgesv does not perform LU decomposition when nhrs=0

[jpittner2]

Openblas dgesv routine does not perform the LU decomposition when nhrs=0 and leaves the matrix and ipiv untouched.
I relied on LU decomposition being performed even when there is no RHS to solve for the computation of determinant.
MKL libraries work in this way and previous openblas version seemed to do so as well.
I think when the user calls the routine with nrhs=0 it should be supposed that he has some reason to do so.
Probably the same holds for dspsv etc.
I noticed this in the version 0.3.31 installed on gentoo linux, but the problem should be system-independent.

[martin-frbg]

This deviation appears to have been introduced with the reimplementation of ?GESV in 2014 - trivial to fix in the interface, but needs to be seen if the functions downstream from there actually handle n=0 well.