cmake: make gio more flexible on linux

Change-Id: I6512a91d4a6fdf7d3b83891f60b19cf25e63cf06
Reviewed-on: http://gerrit.aldebaran.lan/36577
Tested-by: gerrit
Reviewed-by: jmassot <jmassot@aldebaran-robotics.com>
Tested-by: jmassot <jmassot@aldebaran-robotics.com>
Reviewed-by: smartin <smartin@aldebaran-robotics.com>
Tested-by: smartin <smartin@aldebaran-robotics.com>