This is why projects over a certain dollar amount increasingly make me nervous. Half a million dollars wasn't enough for them to do what they needed to do? Again, this is why I'm less inclined to support anyone but bedroom developers. Kickstarter is not a way to pay your office rent or support a whole team of people.
Kickstarter is a combined seed round/market study, nothing more. Anyone outside tiny bedroom developers is going to be using it as leverage for an angel or VC round.
As much as CLANG has the "cool factor" going for it, it needs a lot more than your garden variety game developer (who I have mad respect for, but are on the low end of the developer salary scale). The type of people they needed to hire to make CLANG's hardware and software happen have specialized skill sets and aren't going to come cheap.
To give some perspective, $500,000 would not be enough to pay for a year of work from a team of 4 A+ developers ($100,000+ salary, plus unemployment insurance, taxes, office space, equipment, and any benefits). I highly doubt a complicated project like CLANG can settle for "did a few student projects and wants to do something cool"-type developers (not to imply that those types of developers are bad, they just don't have the right experience for this project).
So no, half a million dollars was NOT enough for them, and it would be completely unreasonable for anyone to expect them to get much of anything done on a mere half million dollar budget. The Kickstarter was always leverage for larger investment.