Fix some compile warnings for LLVM 3.0
Fix a compile error with LLBM 3.3
Attribute holds no longer multiple values in LLVM 3.3.

The solution is to replace Attribute with AttrBuilder in IrFuncTyArg.
Then the argument attributes can be easily manipulated and transformed
into the final AttributeSet.
Merge branch 'master' into merge-2.061-2