Linux: drop bundled tarball

After we drop libevent from #385 the bundled tarball will only provide libpcre2 in addition to libgc, that is already distributed in the main tarball.

Instead we could merely distribute `libpcre2.a` in the main Linux tarball as it can be useful, for example avoid wondering why a program fails to build (actually fails to link) after we happened to add a regular expression which can be frustrating.