Use man page date instead of build date

in order to make builds reproducible.
See https://reproducible-builds.org/ for why this is good.

diff --git a/Makefile b/Makefile
index dae161c..8c5f0b7 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -27,7 +27,7 @@ install: all
        install -d $(MANPREFIX)/man1
        @sed -e "s!VERSION!$(version)!g" \
                -e "s!PREFIX!$(PREFIX)!g" \
-               -e "s!DATE!`date +'%m %Y'`!g" $(DOCDIR)/vimb.1 > $(MANPREFIX)/man1/vimb.1
+               -e "s!DATE!`date -u -r $(DOCDIR)/vimb.1 +'%m %Y' 2>/dev/null || date +'%m %Y'`!g" $(DOCDIR)/vimb.1 > $(MANPREFIX)/man1/vimb.1
        @# .desktop file
        install -d $(DOTDESKTOPPREFIX)
        install -m 644 vimb.desktop $(DOTDESKTOPPREFIX)/vimb.desktop