is not correct. The code works by accident because gzFile is
currently defined as void *, and internally it would be casted from
or to its real type.
A newer version of zlib will instead define it as a pointer to a
specific type pointer (namely, struct gzFile_s *). This therefore
would cause stricter checks and compiler would catch this type
mismatch.
This change does not cause any changes to the resulting binary,
as validated with md5(1).
MFC after: 3 days
6c49347e3e