diff --git a/rtl/unix/cwstring.pp b/rtl/unix/cwstring.pp
index c9068c5062..688bc55fdf 100644
--- a/rtl/unix/cwstring.pp
+++ b/rtl/unix/cwstring.pp
@@ -33,7 +33,7 @@ implementation
 {$endif}
 
 {$ifdef netbsd}
-  {$ifdef TEST_ICONV_LIBC}
+  {$ifndef DISABLE_ICONV_LIBC}
     {$define iconv_is_in_libc}
   {$endif}
 {$endif}