GCi/GCalc: avoid over-linking because of .pc file

Please, correct me if I am wrong, but looking at the source, the mentioned packages are required not as libs but just their headers. The public headers "gcalc.h" and "gci.h" include several external headers (GTK+, GLib, GObject, …), yes. However, because those are specified not as Requires.private but Requires the command

pkg-config --libs gcalc-2

gives

-lgcalc-2 -lgio-2.0 -lgee-0.8 -lgobject-2.0 -lglib-2.0

However, the runtime shared library is already linked to those and just -lgcalc-2 is required for linking to all, see the Guide to pkg-config. If I am wrong, please, add a comment to the .pc files why those libraries are needed.