The configure output mentions that gtksourceview-2.0 is not installed, but while installing libgtksourceview2.0-dev removes that warning, it doesn't change the end result.
I had seen the warning, but as it's not listed as a prerequisite, ./configure doesn't find it critical enough to fail, and the error doesn't look related to viewing source, I didn't believe that could be the issue - and it wasn't.
.Henrik