sokol_app.h: fix size-changed check in _sapp_win32_update_dimensions()

The size-changed check was misfiring each frame when the window
was minimized and the client rectangle is size 0x0, which caused
a redundant reallocation of the DXGI render targets. Thanks to
@nyalloc for discovering the issue.

sokol_app.h

@@ -5905,18 +5905,18 @@ _SOKOL_PRIVATE bool _sapp_win32_update_dimensions(void) {
     if (GetClientRect(_sapp.win32.hwnd, &rect)) {
         _sapp.window_width = (int)((float)(rect.right - rect.left) / _sapp.win32.dpi.window_scale);
         _sapp.window_height = (int)((float)(rect.bottom - rect.top) / _sapp.win32.dpi.window_scale);
-        const int fb_width = (int)((float)_sapp.window_width * _sapp.win32.dpi.content_scale);
-        const int fb_height = (int)((float)_sapp.window_height * _sapp.win32.dpi.content_scale);
+        int fb_width = (int)((float)_sapp.window_width * _sapp.win32.dpi.content_scale);
+        int fb_height = (int)((float)_sapp.window_height * _sapp.win32.dpi.content_scale);
+        /* prevent a framebuffer size of 0 when window is minimized */
+        if (0 == fb_width) {
+            fb_width = 1;
+        }
+        if (0 == fb_height) {
+            fb_height = 1;
+        }
         if ((fb_width != _sapp.framebuffer_width) || (fb_height != _sapp.framebuffer_height)) {
             _sapp.framebuffer_width = fb_width;
             _sapp.framebuffer_height = fb_height;
-            /* prevent a framebuffer size of 0 when window is minimized */
-            if (_sapp.framebuffer_width == 0) {
-                _sapp.framebuffer_width = 1;
-            }
-            if (_sapp.framebuffer_height == 0) {
-                _sapp.framebuffer_height = 1;
-            }
             return true;
         }
     }