remove unnecessary libS logic (closes: #1146381)

remove unnecessary libS logic (closes: #1146381)

This code wasn't doing anything in Debian (since "@libdir@" is always
already on the search path), but the difference in the pcre2-config
file itself was causing multi-arch problems, so remove it.

[similar to our older fix for #805941 which I thought wasn't necessary
any more because the output was always empty on Debian, but I'd missed
that it made the file itself different on different arches, which is a
multi-arch issue]