Don't explicitly use shared_library on gplugin, gplugin-gtk3, and gplugin-gtk4
Review Request #1346 — Created March 14, 2022 and submitted — Latest diff uploaded
By just using the library function meson can choose to static link these into another target.
Did intial testing in the pidgin tree by hacking
gplugin/meson.buildand usedlddto verify that gplugin was staticly linked and that plugins still worked.