Hi!
While conducting a study inspired by the "reproducible builds" practice [1], we have noticed that the package djvulibre could not be built reproducibly.

After investigation, we observe that the unreproducibility is caused by "desktopfiles/Makefile.in", in which the command gzip is invoked without the "-n" argument. Consequently, timestamp is captured in the built file "share/icons/hicolor/scalable/mimetypes/djvu.svgz".

The attached patch adds the argument to the gzip command. Once applied, djvulibre could be built reproducibly.

 [1]: https://wiki.debian.org/ReproducibleBuilds