Preserve ExtParameterInfos into CGFunctionInfo.

As part of this, make the function-arrangement interfaces
a little simpler and more semantic.

NFC.

llvm-svn: 263191
diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index 950781a..5b5afba 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -2159,8 +2159,7 @@
   // Create the function declaration.
   FunctionType::ExtInfo ExtInfo;
   const CGFunctionInfo &FuncInfo =
-      CGM.getTypes().arrangeFreeFunctionDeclaration(Ctx.VoidTy, Args, ExtInfo,
-                                                    /*IsVariadic=*/false);
+    CGM.getTypes().arrangeBuiltinFunctionDeclaration(Ctx.VoidTy, Args);
   llvm::FunctionType *FuncLLVMTy = CGM.getTypes().GetFunctionType(FuncInfo);
 
   llvm::Function *F =