This will enable them to be individually fixed up to use memory if it 
was provided by the caller.

rpcrt4: EmbeddedPointerUnmarshall doesn't need to change the address of the allocated memory, so reduce the level of indirection of the memory parameter by one.

rpcrt4: Errors in sending or receiving packets should result in RPC_S_CALL_FAILED being returned, not RPC_S_PROTOCOL_ERROR.

rpcrt4: Check there is enough space in the buffer and that the size doesn't cause an overflow when copying data to it.

Rename safe_buffer_copy to safe_copy_from_buffer.

OpenGL drivers do not support some low precision internal formats
like GL_RGB5 for fbo color targets. Direct3D application depend on them,
so provide a fallback format for render targets if the requested format
itself is not supported.