[bug#70169] [PATCH 4/7] maint: Help help2man generate reproducible man-pages.

[Janneke Nieuwenhuizen <janneke@gnu.org>]

* doc/local.mk (SOURCE_DATE_EPOCH): New exported variable.

Change-Id: I6636693695d5502657f1475d93d31949e0b0b39d
---
 doc/local.mk | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/doc/local.mk b/doc/local.mk
index 4c8c852657..99a7e84361 100644
--- a/doc/local.mk
+++ b/doc/local.mk
@@ -224,6 +224,9 @@ gen_man =						\
   $(HELP2MANFLAGS)
 
 HELP2MANFLAGS = --source=GNU --info-page=$(PACKAGE_TARNAME)
+# help2man reproducibility
+SOURCE_DATE_EPOCH = $(shell git show HEAD --format=%ct --no-patch 2>/dev/null || echo 0)
+export SOURCE_DATE_EPOCH
 
 $(srcdir)/%D%/guix.1: scripts/guix.in $(sub_commands_mans)
 	-$(AM_V_HELP2MAN)$(gen_man) --output="$@" `basename "$@" .1`
-- 
2.41.0