[PATCH wayland] extend WAYLAND_DISPLAY semantic and make server socket path configurable using environment

[Bill Spitzak]

On 03/11/2015 07:05 PM, Bryce Harrington wrote:

> In any case, may as well check for error return from snprintf
> (i.e. name_size < 0).

snprintf returns the number of bytes that would be needed, so truncation 
is indicated by returning a value greater than the size of the buffer.

(yes a whole lot of old versions of Unix and Windows got this wrong, but 
I don't think Wayland ports to them anyway...)