Wow, changing the default flags sure caused a lot of new warnings.
A lot of the implicit declarations were indeed pointing out code deficiencies
(prototype in a non-included header, or no prototype at all). I fixed all
of these.
In some cases it was best to actually move the routine to another file.

I fixed the warnings in MenuNameToItem and for saveAnimate.

I also had a look to the warnings about signedness and char used as index,
and I think these are appropriately solved now too. If I now do a standard
'make', it is completely free of warnings again.