MinGW: Fix Windows build

modules/juce_gui_basics/native/juce_win32_Windowing.cpp

@@ -715,7 +715,9 @@ static void setWindowZOrder (HWND hwnd, HWND insertAfter)
 }
 
 //==============================================================================
+#if ! JUCE_MINGW
 extern RTL_OSVERSIONINFOW getWindowsVersionInfo();
+#endif
 
 double Desktop::getDefaultMasterScale()
 {
@@ -735,6 +737,7 @@ class Desktop::NativeDarkModeChangeDetectorImpl
 public:
     NativeDarkModeChangeDetectorImpl()
     {
+       #if ! JUCE_MINGW
         const auto winVer = getWindowsVersionInfo();
 
         if (winVer.dwMajorVersion >= 10 && winVer.dwBuildNumber >= 17763)
@@ -751,6 +754,7 @@ public:
                     darkModeEnabled = shouldAppsUseDarkMode() && ! isHighContrast();
             }
         }
+       #endif
     }
 
     bool isDarkModeEnabled() const noexcept  { return darkModeEnabled; }