Bzip3

* Wrap up all the changes from v1.3; bump up the minor version release.
* Various changes for CMake; bundle CMake files with the autotools dist tarball.
* Support for linking with C++.

* Add the `-r` option ("recovery"). If a file fails to decompress fully (e.g. due to a CRC error), ignore it and write the
file regardless.
* Add preliminary CMake support.
* Fix the include guard macro name to work with pedantic compilers.
* Fix the shift direction in the crc32 check function. Because of a programming mistake, v1.3.0 and v1.3.1
introduced a breaking change to the CRC calculation code. The change has been reverted in this release.
While the archives created with these versions of bzip3 will fail to regularly decompress due to a checksum
error, using the recovery option as `bzip3 -rd` to decompress will
restore their original contents.

* Verbose mode in the tool now prints the extra statistics also during testing, not just encoding or decoding.
* Update the CI pipeline to Debian Bullseye.
* Fix a minor issue with side effects in RLE decoding.
* Explicitly disable `-march=native` for releases.
* Fix a bug in the tool reported by Adam Borowski regarding -t/-d input buffer checks.
* Fix an issue with the current input offset not being taken into account in bz3_compress.

* resolve alignment issues on SPARC/s390x.
* fix the security issues arising from libsais.
* due to these changes, updating is strongly encouraged.

* fix an important regression introduced in pull request 55 regarding I/O in main.c
* slightly enlargen the SAIS buffer beyond the documented recommended size to avoid some memory errors in libsais
* properly handle a scenario where the individual block original size is larger than the block size declared in the file header
* further security fixes: strict check for size_src overflow of badly bounded b1, store mode: checking for truncation
mRLE: decoding bounds, bz3_bound in bz3_decompress

* safety fixes for the LZP pass.
* add the `-k` compatibility flag.
* use `env` to detect the shell in bzip3 utility scripts
* update libtool to v2.4.7