There isn't libtiff4-dev package since 14.10, only libtiff5-dev. The easiest fix is to bump to libtiff5-dev, there is no reason to have libtiff4-dev for 14.04 LTS users, because libtiff4-dev and libtiff5-dev is same on 14.04. And Older release aren't supported.
Created attachment 252716 [details] Patch
Comment on attachment 252716 [details] Patch rs=me
Comment on attachment 252716 [details] Patch Clearing flags on attachment: 252716 Committed r184057: <http://trac.webkit.org/changeset/184057>
All reviewed patches have been landed. Closing bug.