egl: wayland: Print out also the actual error on fatal error

Not everything sets errno when returning an error, but they do seem
to return strerror-compatible errors.

So let's try to print those out and also errno if it is set so we
see if there is additional info reported there.

Signed-off-by: Kalle Vahlman <kalle.vahlman@movial.com>
Merge pull request #164 from kvahlman/better-fatal-error-print

egl: wayland: Print out also the actual error on fatal error