diff -ur stan-0.4.orig/src/data.c stan-0.4/src/data.c
--- stan-0.4.orig/src/data.c	2003-12-10 21:29:29.000000000 +0100
+++ stan-0.4/src/data.c	2005-08-19 11:51:09.000000000 +0200
@@ -42,6 +42,7 @@
 #include <ctype.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <errno.h>
 
 #if HAVE_ALLOCA_H
 #include <alloca.h>
diff -ur stan-0.4.orig/src/stan.c stan-0.4/src/stan.c
--- stan-0.4.orig/src/stan.c	2003-12-10 21:29:29.000000000 +0100
+++ stan-0.4/src/stan.c	2005-08-19 11:51:28.000000000 +0200
@@ -39,6 +39,7 @@
 #include <math.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <errno.h>
 
 #include <stan.h>
 #include <data.h>