-Use the shlibs file automatically generated by dh_makeshlibs for the named
-package as a kind of automatically generated shlibs.local file. You can use
-this switch in concert with the -l switch to make dpkg-shlibdeps find a
-library built as part of the current package, and get the shlibs information.
-See example below.
+With recent versions of B<dpkg-shlibdeps>, this option is generally not
+needed, unless your package builds multiple flavors of the same library.
+
+It tells B<dpkg-shlibdeps> (via its B<-S> parameter) to look first in the package
+build directory for the specified package, when searching for libraries,
+symbol files, and shlibs files.