check_compress_algo): Add bzip2.
* compress.c (compress_filter): Make static to help force the use of
push_compress_filter. Remove default algorithm setting since that is done
in push_compress_filter now.
* main.h: Use named algorithm.
* filter.h, compress.c (push_compress_filter, push_compress_filter2): New.
Figure out which is the appropriate compression filter to use, and push it
into place.
* compress.c (handle_compressed), encode.c (encode_simple, encode_crypt),
sign.c (sign_file, sign_symencrypt_file), import.c (read_block), export.c
(do_export): Use push_compress_filter instead of pushing the compression
filter ourselves.
* compress-bz2.c: New. Bzlib versions of the compression filter routines.
* Makefile.am: Include compress-bz2.c if bz2lib is available.
* encode.c (encode_simple,encode_crypt): Use new style CTB for
compressssed packets when using MDC. We need to do this so that
concatenated messages are properly decrypted. Old style
compression assumes that it is the last packet; given that we
can't determine the length in advance, the uncompressor does not
know where to start. Actually we should use the new CTB always
but this would break PGP 2 compatibility.
* parse-packet.c (parse): Special treatment for new style CTB
compressed packets.
* build-packet.c (do_mdc): Removed. Was not used.
(do_encrypted_mdc): Count the version number and the MDC packet.
