[MPlayer-dev-eng] CRC32 function needed

[Ingo Brückl]

For improvements of the scrolling function (dynamic labels) I need to check
whether the string to scroll has changed. In order not to waste memory and
storing it for comparison, it seems simplest to calculate a CRC32 checksum
and store this instead.

I've found a CalcCRC32() function in libmpdemux/muxer_mpeg.c but am not sure
whether this will always be compiled regardless of the user's configuration
(it seems that this only goes in mencoder).

Further on, this function calculates its table every time it is called. If
called often, it might be better this table would be precalculated and
stored.

Some time ago I wrote a CRC32 function without table usage that I could use
instead if CalcCRC32() isn't the one to go with but I don't want to
needlessly increase MPlayer's size if not necessary either.

Ingo