diff --git a/configure.ac b/configure.ac
index 8dd502c..5a26ce1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -265,6 +265,82 @@ AC_DEFUN([UTILS_FUNC_DIRFD],
 
 UTILS_FUNC_DIRFD
 
+#
+# iconv
+#
+
+dnl This macros shamelessly stolen from
+dnl http://gcc.gnu.org/ml/gcc-bugs/2001-06/msg01398.html.
+dnl Written by Bruno Haible.
+
+AC_DEFUN([UTILS_FUNC_ICONV],
+[
+  dnl Some systems have iconv in libc, some have it in libiconv (OSF/1 and
+  dnl those with the standalone portable GNU libiconv installed).
+
+  AC_ARG_WITH([libiconv-prefix],
+[  --with-libiconv-prefix=DIR  search for libiconv in DIR/include and DIR/lib], [
+    for dir in `echo "$withval" | tr : ' '`; do
+      if test -d $dir/include; then CPPFLAGS="$CPPFLAGS -I$dir/include"; fi
+      if test -d $dir/lib; then LDFLAGS="$LDFLAGS -L$dir/lib"; fi
+    done
+   ])
+
+  AC_CACHE_CHECK(for iconv, am_cv_func_iconv, [
+    am_cv_func_iconv="no, consider installing GNU libiconv"
+    am_cv_lib_iconv=no
+    AC_TRY_LINK([#include <stdlib.h>
+#include <iconv.h>],
+      [iconv_t cd = iconv_open("","");
+       iconv(cd,NULL,NULL,NULL,NULL);
+       iconv_close(cd);],
+      am_cv_func_iconv=yes)
+    if test "$am_cv_func_iconv" != yes; then
+      am_save_LIBS="$LIBS"
+      LIBS="$LIBS -liconv"
+      AC_TRY_LINK([#include <stdlib.h>
+#include <iconv.h>],
+        [iconv_t cd = iconv_open("","");
+         iconv(cd,NULL,NULL,NULL,NULL);
+         iconv_close(cd);],
+        am_cv_lib_iconv=yes
+        am_cv_func_iconv=yes)
+      LIBS="$am_save_LIBS"
+    fi
+  ])
+  if test "$am_cv_func_iconv" = yes; then
+    AC_DEFINE(HAVE_ICONV, 1, [Define if you have the iconv() function.])
+    AC_MSG_CHECKING([for iconv declaration])
+    AC_CACHE_VAL(am_cv_proto_iconv, [
+      AC_TRY_COMPILE([
+#include <stdlib.h>
+#include <iconv.h>
+extern
+#ifdef __cplusplus
+"C"
+#endif
+#if defined(__STDC__) || defined(__cplusplus)
+size_t iconv (iconv_t cd, char * *inbuf, size_t *inbytesleft, char * *outbuf, size_t *outbytesleft);
+#else
+size_t iconv();
+#endif
+], [], am_cv_proto_iconv_arg1="", am_cv_proto_iconv_arg1="const")
+      am_cv_proto_iconv="extern size_t iconv (iconv_t cd, $am_cv_proto_iconv_arg1 char * *inbuf, size_t *inbytesleft, char * *outbuf, size_t *outbytesleft);"])
+    am_cv_proto_iconv=`echo "[$]am_cv_proto_iconv" | tr -s ' ' | sed -e 's/( /(/'`
+    AC_MSG_RESULT([$]{ac_t:-
+         }[$]am_cv_proto_iconv)
+    AC_DEFINE_UNQUOTED(ICONV_CONST, $am_cv_proto_iconv_arg1,
+      [Define as const if the declaration of iconv() needs const.])
+  fi
+  LIBICONV=
+  if test "$am_cv_lib_iconv" = yes; then
+    LIBICONV="-liconv"
+  fi
+  AC_SUBST(LIBICONV)
+])
+
+UTILS_FUNC_ICONV
+LIBS="$LIBS $LIBICONV"
 
 #
 # IPv6
diff --git a/rdp.c b/rdp.c
index 7e9164f..4931dea 100644
--- a/rdp.c
+++ b/rdp.c
@@ -27,6 +27,10 @@
 #ifdef HAVE_ICONV_H
 #include <iconv.h>
 #endif
+
+#ifndef ICONV_CONST
+#define ICONV_CONST ""
+#endif
 #endif
 
 extern uint16 g_mcs_userid;
@@ -173,7 +177,7 @@ rdp_out_unistr(STREAM s, char *string, int len)
 				g_codepage, WINDOWS_CODEPAGE, (int)iconv_h);
 			return;
 		}
-		if (iconv(iconv_h, (const char**)&pin, &i, &pout, &o) == (size_t)-1)
+		if (iconv(iconv_h, (ICONV_CONST char**)&pin, &i, &pout, &o) == (size_t)-1)
 		{
 			iconv_close(iconv_h);
 			iconv_h = (iconv_t)-1;
@@ -183,7 +187,7 @@ rdp_out_unistr(STREAM s, char *string, int len)
 		pin = string; pout = s->p;
 	}
 
-	if (iconv(iconv_h, (const char**)&pin, &ibl, &pout, &obl) == (size_t)-1)
+	if (iconv(iconv_h, (ICONV_CONST char**)&pin, &ibl, &pout, &obl) == (size_t)-1)
 	{
 		iconv_close(iconv_h);
 		iconv_h = (iconv_t)-1;
@@ -242,7 +246,7 @@ rdp_in_unistr(STREAM s, char *string, int uni_len)
 		}
 	}
 
-	if (iconv(iconv_h, (const char**)&pin, &ibl, &pout, &obl) == (size_t)-1)
+	if (iconv(iconv_h, (ICONV_CONST char**)&pin, &ibl, &pout, &obl) == (size_t)-1)
 	{
 		iconv_close(iconv_h);
 		iconv_h = (iconv_t)-1;