Pb while compiling code using LLVM API in Xcode 4.2

Hello,

I installed LLVM without problem.

I try to build a simple program using LLVM API for code generation from my own AST.
I am using Xcode 4.2 for my project with LLVM3 compiler.
I setup HeaderSearchPath and LIbSearchPath according my LLVM installation.
However I have compilation errors while compiling my source code in standard file !

Why?

NB: there are no syntax errors in my code, if i follow the procedure to setup a sample project using make it works.

Thanks
jm