configure: try pkg-config for curses

Static linkikng against ncurses may require explicit -ltinfo.
In case -lcurses and -lncurses both didn't work give pkg-config a
chance.

Fixes #1094786 for me.

Signed-off-by: Vadim Evard <v.e.evard@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>