Add support for MAKEPOINTS, GET_X_LPARAM, GET_Y_LPARAM macros

Problem

Each developer has to go out of their way to implement the MAKEPOINTS, GET_X_LPARAM, GET_Y_LPARAM macros manually when converting C++ code examples to C#. This adds one more point where bugs can be introduced, and slows down porting code due to this special case.

These are also some of the most basic and widely used macros, as they are used for handling clicks on forms. They are commonly found in Hello World Win32 examples. https://learn.microsoft.com/en-us/windows/win32/inputdev/wm-lbuttonup

Solution

Add the macros just like the opposite macros, which already exist, to combine shorts into a single int.

Alternative

Each developer has to go out of their way to implement this macro manually when converting C++ code examples to C#.

POINTS p = new ()
{
  x = (short)lParam,
  y = (short)(lParam >> 16),
};

microsoft / CsWin32