improve the APIs for creating struct and function types with no arguments/elements

to not have to create a temporary vector (in the API at least).  Patch by Jay Foad!

llvm-svn: 74584

llvm/examples/ModuleMaker/ModuleMaker.cpp

@@ -27,8 +27,7 @@ int main() {
   Module *M = new Module("test");
 
   // Create the main function: first create the type 'int ()'
-  FunctionType *FT = FunctionType::get(Type::Int32Ty, std::vector<const Type*>(),
-                                       /*not vararg*/false);
+  FunctionType *FT = FunctionType::get(Type::Int32Ty, /*not vararg*/false);
 
   // By passing a module as the last parameter to the Function constructor,
   // it automatically gets appended to the Module.