Fix the scim_string_view_draw() bug for gtk >= 3.20
Fix the scim_string_view_draw() bug for gtk >= 3.20

scim-im/scim,tzhuan/scim,tzhuan/scim,tzhuan/scim,tzhuan/scim,scim-im/scim,scim-im/scim,scim-im/scim