A new function xbps_find_virtual_pkg_in_dict() has been made public
to the API to make this find duplicate packages in the transaction
when updating packages.
Benchmarks before and after the code for installing
"xorg gnome xbmc vlc firefox epdfview":
OLD
-----------------
real 0m1.844s
user 0m1.841s
sys 0m0.003s
NEW
-----------------
real 0m0.873s
user 0m0.868s
sys 0m0.004s