build the source distribution archives reproducibly * Makefile.am (GZIP_ENV): Override default for a deterministic gzip. (SOURCE_MTIME): Define to the value printed by get-source-mtime.sh. (TAR_OPTIONS): Define to GNU tar options for making deterministic archives and export for tar to inherit by default. * build-aux/get-source-mtime.sh: New script. * build-aux/module.mk (EXTRA_DIST): Include it in the list. * m4/acinclude.m4 (OCTAVE_PROG_TAR_REPRODUCIBLE): New macro. * configure.ac: Use it.

--- a/build-aux/module.mk	Tue Oct 11 15:20:35 2016 +0200
+++ b/build-aux/module.mk	Thu Sep 21 14:19:10 2017 -0700
@@ -5,6 +5,7 @@
   %reldir%/check-subst-vars.in.sh \
   %reldir%/find-defun-files.sh \
   %reldir%/find-files-with-tests.sh \
+  %reldir%/get-source-mtime.sh \
   %reldir%/mk-hg-id.sh \
   %reldir%/mk-octave-config-h.sh \
   %reldir%/mk-opts.pl \