Linked iconv when compile libShoebill.so.
Linked iconv when compile libShoebill.so.

Signed-off-by: JingLin Wang <6ca2e7e74c7cf3df5faac1534c66bedaa36ba6fc@gmail.com>

Shoebill/ShoebillPlugin,Shoebill/ShoebillPlugin,Shoebill/ShoebillPlugin