--- a/src/charset.c
+++ b/src/charset.c
@@ -159,7 +159,7 @@
  * NAME:	charset->latin1()
  * DESCRIPTION:	return a Latin-1 (ISO 8859-1) string for MacOS Standard Roman
  */
-char *cs_latin1(char *mstr, int *lenptr)
+char *cs_latin1(char *mstr, size_t *lenptr)
 {
     int		    ilen, olen, i;
     char	    *latin1, *ptr;
--- a/src/charset.h
+++ b/src/charset.h
@@ -23,6 +23,9 @@
  *
  * $Id: charset.h,v 1.1.1.1 2002/03/05 19:50:29 klaus Exp $
  */
+
+#include <stddef.h>
+
     /* a two byte unicode character, gnus wchar_t is 4 bytes in linux */
 typedef unsigned short UCS2;
 
@@ -35,7 +38,7 @@
      * lenptr may be null in wich case the given strs len is used.
      * on return *lenptr is set to the returned strings len.
      * must be free()d */
-char *cs_latin1(char *, int *);
+char *cs_latin1(char *, size_t *);
 
     /* return a MacOS Standard Roman string for Latin-1 (ISO 8859-1).
      * lenptr may be null in wich case the given strs len is used.