M configure.in → configure.in

@@ -96,18 +96,17 @@ if test "x$ac_found_iconv" = "xyes"; then
   AC_CACHE_CHECK(for iconv declaration, ac_cv_iconv_const,
     [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stdlib.h>
         #include <iconv.h>]],
-        [[#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]])],
-      [ac_cv_iconv_const=],
-      [ac_cv_iconv_const=const])])
-  AC_DEFINE_UNQUOTED([HAVE_CONST_ICONV], $ac_cv_iconv_const,
-    [Define as const if the declaration of iconv() needs const.])
+        [[
+            char **msg, **new_msg; 
+            size_t result, inleft, outleft; 
+            result = iconv((iconv_t)(-1), msg, &inleft, new_msg, &outleft);
+            return 0;
+         ]])],
+      [ac_cv_iconv_const=no],
+      [ac_cv_iconv_const=yes])])
+  if test "x$ac_cv_iconv_const" = xyes; then
+    AC_DEFINE(HAVE_CONST_ICONV, 1, [Define if you have the iconv() function.])
+  fi
 fi