Hi Darren,
I just tried to compile vtg with gtksourcecompletion 0.7.0 and it
compiles without any errors. So can you check if your environment
satisfies these requirements?
1) vala compiler should be the new 0.7.6 or at least the more recent
than commit 66ee67c85209b6cbc8f488c2bd003b0bc3a9fc3b (the 0.7.0 or 0.7.5
versions aren't enough)
2) Gtk Source Completion should be the 0.7.0 version
(http://cloud.github.com/downloads/chuchiperriman/gtksourcecompletion/gtksourcecompletion-0.7.0.tar.gz)
If these requirements are satisfied, maybe the cause is that you haven't
done a clean build of vtg.
Just try with these commands (in the vtg main directory):
1) rm */*.stamp
2) make clean
3) make
the first command with force the build system to recompile all the vala
files.
I hope this helps.
Ciao,
Andrea