This PR updates allegro to the last 4.1.4, fixes allegro-config,
and adds samples.
Note: it is an "in progress version", and we could make a new port
allegro-devel, but I do not think that it is useful.
Fix: Remark: if this PR were committed before PR ports/45176, it can be
Please apply this patch:
(new file: files/patch-misc::allegro-config.in)