Refactor SDL device to use the same abstraction as other devices

In particular this makes the OpenGL procedure stuff work.
fixes https://github.com/minetest/minetest/issues/12265

source/Irrlicht/CSDLManager.cpp

@@ -0,0 +1,56 @@
+// Copyright (C) 2022 sfan5
+// This file is part of the "Irrlicht Engine".
+// For conditions of distribution and use, see copyright notice in Irrlicht.h
+
+#include "CSDLManager.h"
+
+#if defined(_IRR_COMPILE_WITH_SDL_DEVICE_) && defined(_IRR_COMPILE_WITH_OPENGL_)
+
+#include "CIrrDeviceSDL.h"
+#include "COpenGLCommon.h"
+
+namespace irr
+{
+namespace video
+{
+
+CSDLManager::CSDLManager(CIrrDeviceSDL* device) : IContextManager(), SDLDevice(device)
+{
+	#ifdef _DEBUG
+	setDebugName("CSDLManager");
+	#endif
+}
+
+bool CSDLManager::initialize(const SIrrlichtCreationParameters& params, const SExposedVideoData& data)
+{
+	Data = data;
+	return true;
+}
+
+const SExposedVideoData& CSDLManager::getContext() const
+{
+	return Data;
+}
+
+bool CSDLManager::activateContext(const SExposedVideoData& videoData, bool restorePrimaryOnZero)
+{
+	// unclear if this is still needed:
+	glFrontFace(GL_CW);
+	return true;
+}
+
+void* CSDLManager::getProcAddress(const std::string &procName)
+{
+	return SDL_GL_GetProcAddress(procName.c_str());
+}
+
+bool CSDLManager::swapBuffers()
+{
+	SDLDevice->SwapWindow();
+	return true;
+}
+
+}
+}
+
+#endif