Avoid SDL_GetWindowSurface to fix crashes on wayland

Instead of trying to access the wayland window through SDL_GetWindowSurface,
it seems to be easier to just use a pseudo surface which is not really used by
anyone (except the size information).
Save link information in *AL(L) instructions unconditionally

All "Jump and link" and "Branch and link" like instructions save the PC in the
target register unconditionally and not only when the branch/jump is taken.
The specification is not clear whether the store is actually made before or
after the delay slot and therefore the behavior of the dynarecs ("link" before
delay slot) is used.

Reported-by: Nebuleon <nebuleon.fumika@gmail.com>
Merge pull request #8 from ecsv/sdl2_compat

Avoid SDL_GetWindowSurface to fix crashes on wayland
Merge pull request #9 from ecsv/interpreter_link

Save link information in *AL(L) instructions unconditionally
Merge remote-tracking branch 'upstream/master'
core: Sync with upstream.