slatbs(3) on Linux

The text c7cdd4a725aa, as Debian 2.2 (Potato), Debian 2.1 (Slink), Debian 2.0 (Hamm) shipped it.

solve one of the triangular systems A *x = s*b or A'*x = s*b with scaling to prevent overflow, where A is an upper or lower triangular band matrix