feat(build): Accommodate SOURCE_DATE_EPOCH for reproducible builds

sile-typesetter · Dec 30, 2021 · 16c81a8 · 16c81a8
1 parent c389355
commit 16c81a8
Showing 1 changed file with 13 additions and 2 deletions.
diff --git a/configure.ac b/configure.ac
@@ -21,12 +21,23 @@ AC_PROG_SED
 AX_PROGVAR([cmp])
 AX_PROGVAR([git])
 
+DATEFMT='%d %B %Y'
 AM_COND_IF([IS_SDIST],
            [
             AX_PROGVAR([date])
-            MAN_DATE=$($DATE "+%d %B %Y")
+            if test -n "$SOURCE_DATE_EPOCH"; then
+                AX_PROG_DATE([date])
+                AS_VAR_IF([ax_cv_prog_date_gnu], [yes], [
+                           MAN_DATE=$(LC_ALL=C $DATE --utc --date=@$SOURCE_DATE_EPOCH +"$DATEFMT")
+                          ])
+                AS_VAR_IF([ax_cv_prog_date_bsd], [yes], [
+                           MAN_DATE=$(LC_ALL=C TZ=UTC $DATE -r $SOURCE_DATE_EPOCH +"$DATEFMT")
+                          ])
+            else
+                MAN_DATE=$($DATE +"$DATEFMT")
+            fi
            ], [
-            MAN_DATE=$($GIT log -1 --format="%cd" --date=format:"%d %B %Y" -- sile.1.in)
+            MAN_DATE=$($GIT log -1 --format="%cd" --date=format:"$DATEFMT" -- sile.1.in)
            ])
 AC_SUBST([MAN_DATE])