Win32: Fix GLFW_MAXIMIZED not maximizing window

The window rect adjustment for content scale broke the initial, correct
maximization performed when creating the window with WS_MAXIMIZE.  This
switches to updating the restored rect instead of the current rect.

Fixes #1499.
Closes #1503.

(cherry picked from commit 711b9694a133ef338482ae75ada724e3a9915d91)

README.md

@@ -124,6 +124,8 @@ information on what to include when reporting a bug.
    symbol redefinition (#1524)
  - [Win32] Bugfix: The cursor position event was emitted before its cursor enter
    event (#1490)
+ - [Win32] Bugfix: The window hint `GLFW_MAXIMIZED` did not move or resize the
+   window (#1499)
  - [X11] Bugfix: The CMake files did not check for the XInput headers (#1480)
  - [X11] Bugfix: Key names were not updated when the keyboard layout changed
    (#1462,#1528)

src/win32_window.c

@@ -1281,6 +1281,7 @@ static int createNativeWindow(_GLFWwindow* window,
     if (!window->monitor)
     {
         RECT rect = { 0, 0, wndconfig->width, wndconfig->height };
+        WINDOWPLACEMENT wp = { sizeof(wp) };
 
         if (wndconfig->scaleToMonitor)
         {
@@ -1301,10 +1302,11 @@ static int createNativeWindow(_GLFWwindow* window,
         else
             AdjustWindowRectEx(&rect, style, FALSE, exStyle);
 
-        SetWindowPos(window->win32.handle, NULL,
-                     rect.left, rect.top,
-                     rect.right - rect.left, rect.bottom - rect.top,
-                     SWP_NOACTIVATE | SWP_NOZORDER);
+        // Only update the restored window rect as the window may be maximized
+        GetWindowPlacement(window->win32.handle, &wp);
+        wp.rcNormalPosition = rect;
+        wp.showCmd = SW_HIDE;
+        SetWindowPlacement(window->win32.handle, &wp);
     }
 
     DragAcceptFiles(window->win32.handle, TRUE);