Mars does not build against LLVM 3.0

[Matt Giuca]

LLVM 3.0 has changed its exception handling and type system in a serious way, which has broken Mars.

The first error is in building the runtime:
llvm-as: runtime.ll:117:5: error: expected instruction opcode
    unwind
    ^

But there are countless more errors if this one is resolved.

The main problems are that:
- The 'unwind' instruction is gone, so we will have to fall back to setjmp/longjmp error handling.
- Types can no longer have names, except for structs (which now have named equivalence rather than structural equivalence).

[Matt Giuca (mgiuca)]

Fixed in trunk r1364.