diff -u -r ../picoLisp/src/ext.c ./src/ext.c
--- ../picoLisp/src/ext.c	2016-04-01 04:05:10.000000000 -0400
+++ ./src/ext.c	2016-04-13 06:40:31.791712225 -0400
@@ -3,6 +3,7 @@
  */
 
 #include "pico.h"
+#include <crypt.h>
 
 /*** Soundex Algorithm ***/
 static int SnxTab[] = {