Remove support for building with LLVM 2.9.

A forthcoming change uses some features of LLVM 3.0's new type
system, and it's not worth back-porting this to also all work
with LLVM 2.9.

builtins.cpp

@@ -620,9 +620,7 @@ AddBitcodeToModule(const unsigned char *bitcode, int length,
 
         std::string(linkError);
         if (llvm::Linker::LinkModules(module, bcModule, 
-#if defined(LLVM_3_0) || defined(LLVM_3_0svn) || defined(LLVM_3_1svn)
                                       llvm::Linker::DestroySource,
-#endif // LLVM_3_0
                                       &linkError))
             Error(SourcePos(), "Error linking stdlib bitcode: %s", linkError.c_str());
         lSetInternalFunctions(module);