[wip/mk/sysdep] Add a sysdep for liblzma

liblzma is the XZ-format compression library.

XZ is the successor to the Lempel-Ziv/Markov-chain Algorithm compression
format, which provides memory-hungry but powerful compression (often
better than bzip2) and fast, easy decompression.

The native format of liblzma is XZ; it also supports raw (headerless)
streams and the older LZMA format used by lzma.