Add a demo program for mkd_xhtmlpage(), add it to the sample programs list.

makepage.c

@@ -0,0 +1,26 @@
+/*
+ * makepage: Use mkd_xhtmlpage() to convert markdown input to a
+ *           fully-formed xhtml page.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <mkdio.h>
+
+main(argc, argv)
+int argc;
+char **argv;
+{
+    MMIOT *doc;
+    
+    if ( (argc > 1) && !freopen(argv[1], "r", stdin) ) {
+	perror(argv[1]);
+	exit(1);
+    }
+
+    if ( (doc = mkd_in(stdin, 0)) == 0 ) {
+	perror( (argc > 1) ? argv[1] : "stdin" );
+	exit(1);
+    }
+
+    exit(mkd_xhtmlpage(doc, 0, stdout));
+}