diff --git a/acinclude.m4 b/acinclude.m4
index 4db7a360..a282bb0a 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -193,7 +193,7 @@ AC_DEFUN([CURL_CHECK_HEADER_MALLOC], [
     case "$curl_cv_need_header_malloc_h" in
       yes)
         AC_DEFINE_UNQUOTED(NEED_MALLOC_H, 1,
-          [Define to 1 if you need the malloc.h header file.])
+          [Define to 1 if you need the malloc.h header file even with stdlib.h])
         ;;
     esac
   fi