src/wav.c : Fix parsing of malformed LIST chunk.
src/wav.c : Fix parsing of malformed LIST chunk.

Example file provided by Joshua Rogers on the libsndfile-devel
list had the following LIST chunks:

   LIST : 140
     INFO
       ISFT : gvfs-cdda using libcdio 0.81 i486-pc-linux-gnu
       *** ISTR : 12
       IART : Deep Purple
       INAM : Fireball
       *** IPRT : 2
       *** IFRM : 4
   LIST : 64
       *** MID  : 1414676810

Obviously, a LIST chunk 64 byte in size cannot contain another chunk
that is very much larger.

The fix was to make sure that inside a LIST chunks, any unknown chunk
types with impossibly large sizes get handled correctly.

Icenowy/libsndfile,audiokit/libsndfile,Icenowy/libsndfile,erikd/libsndfile,erikd/libsndfile,audiokit/libsndfile,evpobr/libsndfile,libsndfile/libsndfile,libsndfile/libsndfile,evpobr/libsndfile,Icenowy/libsndfile,libsndfile/libsndfile,RonNovy/libsndfile,evpobr/libsndfile,erikd/libsndfile,RonNovy/libsndfile,Icenowy/libsndfile,evpobr/libsndfile,RonNovy/libsndfile,audiokit/libsndfile,libsndfile/libsndfile,audiokit/libsndfile,erikd/libsndfile,Icenowy/libsndfile,evpobr/libsndfile,libsndfile/libsndfile,syb0rg/libsndfile,syb0rg/libsndfile,erikd/libsndfile,syb0rg/libsndfile,RonNovy/libsndfile,syb0rg/libsndfile