GLFW: Null: Fix out parameters not being set

From upstream: https://github.com/glfw/glfw/commit/cd0dc76c7c979fdec0b7b3721e3a91de7a730d0d.

glfw/null_monitor.c

@@ -70,8 +70,12 @@ void _glfwPlatformFreeMonitor(_GLFWmonitor* monitor)
     _glfwFreeGammaArrays(&monitor->null.ramp);
 }
 
-void _glfwPlatformGetMonitorPos(_GLFWmonitor* monitor UNUSED, int* xpos UNUSED, int* ypos UNUSED)
+void _glfwPlatformGetMonitorPos(_GLFWmonitor* monitor UNUSED, int* xpos, int* ypos)
 {
+    if (xpos)
+        *xpos = 0;
+    if (ypos)
+        *ypos = 0;
 }
 
 void _glfwPlatformGetMonitorContentScale(_GLFWmonitor* monitor UNUSED,

glfw/null_window.c

@@ -274,10 +274,25 @@ void _glfwPlatformGetWindowFrameSize(_GLFWwindow* window,
 {
     if (window->null.decorated && !window->monitor)
     {
-        *left = 1;
-        *top = 10;
-        *right = 1;
-        *bottom = 1;
+        if (left)
+            *left = 1;
+        if (top)
+            *top = 10;
+        if (right)
+            *right = 1;
+        if (bottom)
+            *bottom = 1;
+    }
+    else
+    {
+        if (left)
+            *left = 0;
+        if (top)
+            *top = 0;
+        if (right)
+            *right = 0;
+        if (bottom)
+            *bottom = 0;
     }
 }