#12 make build reproducible

[Bernhard M. Wiedemann]

when building packages (e.g. for openSUSE Linux)
(random) filesystem order of input files
influences ordering of functions in the output,
thus without the patch, builds (in disposable VMs) would usually differ.

See https://reproducible-builds.org/ for why this matters.

[Thomas Holder]

patch applied in svn rev 4175