+# If not specified in the command line, get gen_origin from the existing
+# ChangeLog file.
+[ "$gen_origin" ] || {
+ gen_origin_line=`
+ grep -E '^commit [0-9a-f]+ [(]inclusive[)]' ChangeLog.$nmax
+ ` || {
+ printf '%s\n' "ChangeLog.$nmax lacks a 'commit ... (inclusive)' line" >&2
+ exit 1
+ }
+ set $gen_origin_line
+ gen_origin=$2
+}
+
+# Get the new value for gen_origin from the latest version in the repository.
+new_origin=`git log --pretty=format:%H 'HEAD^!'` || exit
+