as the "where to put the packet data" argument.
This lets more of the libwiretap code be common between the read and
seek-read code paths, and also allows for more flexibility in the "fill
in the data" path - we can expand the buffer as needed in both cases.
svn path=/trunk/; revision=49949
for read and seek-read.
Clarify a comment. (wtap_open_offline() only rewinds the file before
calling each open routine; once one of those routines has decided the
file belongs to it, the seek offset belongs to it, so it needs to do all
the seeking necessary - files with a file header *don't* want a rewind,
they want to leave the seek offset positioned *past* the file header so
it can read the records that follow the file header.)
svn path=/trunk/; revision=49347