v5.4.2
tuklib_physmem: Silence warning from -Wcast-function-type on MinGW-w64.
Bump version and soname for 5.4.2.
Build: Prepare to support Automake's subdir-objects.
xzdiff: Add support for .lz files.
Change a few HTTP URLs to HTTPS.
Build: Add support for translated man pages using po4a.