Better support for ldconfig

[skalee]

Right now running ldconfig is coupled with installing gnupg component with --sudo option on. This is suboptimal.

1. One may want to install with --sudo on, but for some reason would rather like skip ldconfig (e.g. on system in which it works in a slightly different way than this scripts expects)
2. One may want to run scripts as root and without sudo (which may come handy in Docker, esp. when testing)
3. One may want to build gpgme right after gnupg, in this case ldconfig happens too early
4. One may want to build some components, but not gnupg (e.g. when building gpgme)
5. Maybe something else

Anyway, I suppose that running ldconfig should happen after building each individual component, and should be steered by some other option than --sudo. Also, in far future sudo -c could be added for sudoless systems.