Fix debugging issues with SBCL.

git-svn-id: https://fricas.svn.sourceforge.net/svnroot/fricas/trunk@1539 b0c55286-4f34-0410-a049-a1e7e93b0762
Make linear dependence more consistent with linear solvers.


git-svn-id: https://fricas.svn.sourceforge.net/svnroot/fricas/trunk@1540 b0c55286-4f34-0410-a049-a1e7e93b0762