gv_doc_template.tcl: Pass "-gmt True" to support reproducible dates.
While the code already uses SOURCE_DATE_EPOCH
, it also needs to ensure
that the times are emitted in UTC/GMT, otherwise building on machines
configured with different timezones may result in different embedded
timestamps.
I forwarded this from https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=962021
Edited by Bernhard M. Wiedemann