xsl/ddate: fix discordian holidays in leap years

xsl/ddate.xsl

@@ -66,7 +66,16 @@
   <xsl:template name="ddate-holiday">
     <xsl:param name="date"/>
 
-    <xsl:variable name="yday" select="date:day-in-year($date)"/>
+    <xsl:variable name="yday">
+      <xsl:choose>
+	<xsl:when test="date:leap-year($date) and date:month-in-year($date) &gt; 2">
+	  <xsl:value-of select="date:day-in-year($date) - 1"/>
+	</xsl:when>
+	<xsl:otherwise>
+	  <xsl:value-of select="date:day-in-year($date)"/>
+	</xsl:otherwise>
+      </xsl:choose>
+    </xsl:variable>
     <xsl:variable name="mday" select="(($yday - 1) mod 73) + 1"/>
     <xsl:variable name="season" select="floor(($yday - 1) div 73) + 1"/>