libglib2: fix static linking with libgio

libglib2: fix static linking with libgio

When statically linking with libgio, application needs to link with all
internal libraries that libgio uses. This commit adds patch which
includes libmount as Libs.private.

Fixes:
  http://autobuild.buildroot.net/results/fdf/fdf26abbed0014606a7788ce5d60828a0e871186
  http://autobuild.buildroot.net/results/1d6/1d69b8ea34cf57255be54de0c87fc83590fb1337

Cc: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Rahul Bedarkar <rahul.bedarkar@imgtec.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>