Add a port of lzbench, an in-memory benchmark of open-source LZ77/LZSS/LZMA
compressors. It joins all compressors into a single executable. At the
beginning, an input file is read to memory. Then all compressors are used
to compress and decompress the file and decompressed file is verified.

WWW: https://github.com/inikep/lzbench
Add a port of libdeflate, a library for fast, whole-buffer DEFLATE-based
compression and decompression.

WWW: https://github.com/ebiggers/libdeflate

Because GitHub releases (tarballs) are not fetched with correct modification
time, set TIMESTAMP to 1515146810 which corresponds to commit 6c4ad37 tagged
as this release.