Update bot creates PRs for `lua51Packages.libluv` even though the main
package is luv. This commit adds luv to libluv's tests to ensure that
both are tested during automatic updates.
Upstream rockspec file now supports WITH_SHARED_LIBUV variable. This
commit uses it. Before this change, upstream value of WITH_SHARED_LIBUV
overrode the one from the inline patch, which caused a build failure.