Fixed monitor size using wrong incorrect value.

The display device string was used, instead of the adapter device name,
leading to the wrong incorrect physical size being returned for
non-primary monitors.  The right incorrect physical size is now returned
for all monitors.

README.md

@@ -99,6 +99,8 @@ GLFW bundles a number of dependencies in the `deps/` directory.
                    systems
  - [Win32] Bugfix: Gamma ramp functions acted on entire desktop instead of the
                    specified monitor
+ - [Win32] Bugfix: The wrong incorrect physical size was returned for
+                   non-primary monitors
  - [X11] Added run-time support for systems lacking the XKB extension
  - [X11] Made GLX 1.3 the minimum supported version
  - [X11] Replaced `XRRGetScreenResources` with `XRRGetScreenResourcesCurrent`

src/win32_monitor.c

@@ -144,7 +144,7 @@ _GLFWmonitor** _glfwPlatformGetMonitors(int* count)
         display.cb = sizeof(DISPLAY_DEVICEW);
 
         EnumDisplayDevicesW(adapter.DeviceName, 0, &display, 0);
-        dc = CreateDCW(L"DISPLAY", display.DeviceString, NULL, NULL);
+        dc = CreateDCW(L"DISPLAY", adapter.DeviceName, NULL, NULL);
 
         if (adapter.StateFlags & DISPLAY_DEVICE_PRIMARY_DEVICE)
             primaryIndex = found;