[poppler] Requires.private field missing in poppler.pc

[Jeroen Ooms]

On Thu, Mar 22, 2018 at 8:53 AM, suzuki toshiya
<mpsuzuki at hiroshima-u.ac.jp> wrote:
> Dear Jeroen,
>
> Please check https://github.com/mpsuzuki/poppler/tree/for-travis whether it
> can serve for you.

Yes this works! I now get:

pkg-config --libs-only-l poppler-cpp
  -lpoppler-cpp

pkg-config --libs-only-l --static poppler-cpp
-lpoppler-cpp -lpoppler -ljpeg -ltiff -lpng -lfontconfig -lexpat
-lfreetype -lz -lbz2 -lpng16 -lz -lcurl -lldap -lz -llcms2 -lm
-lpthread -lopenjp2 -lm

pkg-config --libs-only-l --static poppler-glib
-lpoppler-glib -lpoppler -ljpeg -ltiff -lpng -lcurl -lldap -lz -llcms2
-lm -lpthread -lopenjp2 -lm -lcairo -lz -lgobject-2.0 -lffi -lglib-2.0
-lintl -lpcre -lintl -liconv -lpcre -lpixman-1 -lfontconfig -lexpat
-lfreetype -lz -lbz2 -lpng16 -lz -lpng16 -lz

Hope this patch will get accepted!