build failed, can't find vala.h

I'm trying to build Scratch.
When I try to build Scratch it fails because it can't find vala.h
I've run "sudo apt-get build-dep scratch" and have valac 0.26.2 and 0.28 installed.

Build log:
shy@shy-elemntry:~/software/sourcecode/scratch/build$ make
[ 21%] Built target scratch-text-editor
[ 42%] Built target scratchcore
[ 44%] Built target contractor
[ 47%] Built target pastebin
[ 53%] Built target filemanager
[ 58%] Built target folder-manager
[ 62%] Built target terminal
[ 65%] Built target browser-preview
[ 67%] Built target strip-trailing-save
[ 70%] Built target open-with
[ 72%] Built target brackets-completion
[ 76%] Built target word-completion
[ 78%] Built target source-tree
[ 80%] Building C object plugins/outline/CMakeFiles/outline.dir/ValaProcessing/ComparisonHelper.c.o
/home/shy/software/sourcecode/scratch/build/plugins/outline/ValaProcessing/ComparisonHelper.c:10:18: fatal error: vala.h: No such file or directory
 #include <vala.h>
                  ^
compilation terminated.
make[2]: *** [plugins/outline/CMakeFiles/outline.dir/ValaProcessing/ComparisonHelper.c.o] Error 1
make[1]: *** [plugins/outline/CMakeFiles/outline.dir/all] Error 2
make: *** [all] Error 2

My OS details are:
shy@shy-elemntry:~/software/sourcecode/scratch/build$ lsb_release -a
No LSB modules are available.
Distributor ID: elementary OS
Description: elementary OS Freya
Release: 0.3
Codename: freya
shy@shy-elemntry:~/software/sourcecode/scratch/build$ uname -a
Linux shy-elemntry 3.16.0-34-generic #47~14.04.1-Ubuntu SMP Fri Apr 10 17:49:16 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux