README: Describe meaning of copyright year ranges.

This is required by the GNU maintainers guide as a prerequisite for using
copyright year ranges.  So far, PSPP itself doesn't use ranges, but Gnulib
(which PSPP uses) does.

diff --git a/README b/README
index d1c78db2c20bca092cbde646171aec4fc78068b6..35e44ae7421f006b5b64c91f49c537f04bf46e77 100644 (file)
--- a/README
+++ b/README
@@ -88,3 +88,6 @@ following:
           statistical procedures is evolving quickly enough that a
           plug-in model does not make sense.  Over the long term, it
           may make sense to introduce plug-ins.
+
+For any copyright year range specified as YYYY-ZZZZ in this package note
+that the range specifies every single year in that closed interval.