Fixed a few godot engine 4 warnings on clang with Opengl and Windows apis.

platform/windows/gl_manager_windows.h

@@ -74,7 +74,6 @@ private:
 	GLWindow *_current_window = nullptr;
 
 	PFNWGLSWAPINTERVALEXTPROC wglSwapIntervalEXT = nullptr;
-	PFNWGLGETSWAPINTERVALEXTPROC wglGetSwapIntervalEXT = nullptr;
 
 	// funcs
 	void _internal_set_current_window(GLWindow *p_win);

platform/windows/os_windows.cpp

@@ -830,7 +830,7 @@ class FallbackTextAnalysisSource : public IDWriteTextAnalysisSource {
 	IDWriteNumberSubstitution *n_sub = nullptr;
 
 public:
-	HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, VOID **ppvInterface) {
+	HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, VOID **ppvInterface) override {
 		if (IID_IUnknown == riid) {
 			AddRef();
 			*ppvInterface = (IUnknown *)this;
@@ -844,11 +844,11 @@ public:
 		return S_OK;
 	}
 
-	ULONG STDMETHODCALLTYPE AddRef() {
+	ULONG STDMETHODCALLTYPE AddRef() override {
 		return InterlockedIncrement(&_cRef);
 	}
 
-	ULONG STDMETHODCALLTYPE Release() {
+	ULONG STDMETHODCALLTYPE Release() override {
 		ULONG ulRef = InterlockedDecrement(&_cRef);
 		if (0 == ulRef) {
 			delete this;