pkgconf: bump to version 0.9.12

Drop patches, they aren't required any more.
It fixes a bug where inline comments cause issues, like:

Libs: -lblah # -lbleh

...it would make pkgconf search for the '#' package

This is required for the nettle 3.1.1 upgrade since howgeed.pc adjusts
Libs according to static/dynamic builds using the comment feature.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>