Added AGC renderer stub.

src/renderer_agc.cpp

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2011-2021 Branimir Karadzic. All rights reserved.
+ * License: https://github.com/bkaradzic/bgfx#license-bsd-2-clause
+ */
+
+#include "bgfx_p.h"
+
+namespace bgfx { namespace agc
+{
+	RendererContextI* rendererCreate(const Init& _init)
+	{
+		BX_UNUSED(_init);
+		return NULL;
+	}
+
+	void rendererDestroy()
+	{
+	}
+
+} /* namespace agc */ } // namespace bgfx