diff --git a/defaults.h b/defaults.h
index f2399aff..949c117e 100644
--- a/defaults.h
+++ b/defaults.h
@@ -13,6 +13,7 @@
 #define SEXP_BSD 1
 #else
 #define SEXP_BSD 0
+#define _GNU_SOURCE
 #endif
 
 #ifndef USE_BOEHM
diff --git a/sexp.c b/sexp.c
index 18b903f7..4b8e0ce5 100644
--- a/sexp.c
+++ b/sexp.c
@@ -559,7 +559,7 @@ sexp sexp_get_output_string (sexp port) {
   fflush(sexp_port_stream(port));
   return sexp_substring(cookie,
                         sexp_make_integer(0),
-                        sexp_string_length(cookie));
+                        sexp_make_integer(sexp_string_length(cookie)));
 }
 
 #endif
diff --git a/sexp.h b/sexp.h
index 9f8d4fe4..c2bccf53 100644
--- a/sexp.h
+++ b/sexp.h
@@ -5,6 +5,9 @@
 #ifndef SEXP_H
 #define SEXP_H
 
+#include "config.h"
+#include "defaults.h"
+
 #include <ctype.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -13,9 +16,6 @@
 #include <sysexits.h>
 #include <math.h>
 
-#include "config.h"
-#include "defaults.h"
-
 /* tagging system
  *   bits end in  00:  pointer
  *                01:  fixnum