Wayland_data_source_send sends an extra null byte

[Guldoman]

When pasting from an SDL Wayland application to another there is an added null byte.

Copying "test" from SDL results in 74 65 73 74 00 (xclip -o -selection clipboard | hexdump -e '/1 "%3.2x"').
Copying "test" from other applications results in 74 65 73 74.

In chromium, pasting text copied from SDL in the address bar results in it showing the added null byte:

Maybe there's no need to copy the null byte to the pipe here:

SDL/src/video/wayland/SDL_waylanddatamanager.c

Lines 266 to 267 in 3bae2d5

	while (write_pipe(fd, mime_data->data, mime_data->length,
	&written_bytes) > 0);

Edit:
Funnily enough, I pasted part of the title from an SDL application running under Wayland and the "null byte" shows up when trying to edit it:

[slouken]

This should fix it. Thanks!

[Guldoman]

It looks like pasting in the same SDL application is now a bit broken 😅.
I'm getting some garbage after the actual content.

Top is the SDL application I'm copying from, bottom is another instance of the same application (or any other application):

I copied 1 from the top application, then pasted three times in both of them.

[slouken]

That was a separate issue, fixed now. Thanks!