diff --git a/acinclude.m4 b/acinclude.m4
index f270888fb08572132a0546ae801f45e9dab70f15..d0fab3db681b12b32032d8f842fdf553bb101492 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -299,7 +299,7 @@ AC_DEFUN([CURL_FUNC_GETNAMEINFO_ARGTYPES], [
   if test "$curl_cv_func_getnameinfo_args" = "unknown"; then
     AC_MSG_WARN([Cannot find proper types to use for getnameinfo args])
     AC_MSG_WARN([Undefining HAVE_GETNAMEINFO])
-    undefine([HAVE_GETNAMEINFO])dnl
+#undef HAVE_GETNAMEINFO
     ac_cv_func_getnameinfo="no"
   else
     gni_prev_IFS=$IFS; IFS=','
diff --git a/ares/acinclude.m4 b/ares/acinclude.m4
index ac8f838088b62ec73f1be4736982063bad99f9a8..f18379abb7eb603c9afb13ff829c156a136f7d3d 100644
--- a/ares/acinclude.m4
+++ b/ares/acinclude.m4
@@ -278,7 +278,7 @@ AC_DEFUN([CURL_FUNC_GETNAMEINFO_ARGTYPES], [
   if test "$curl_cv_func_getnameinfo_args" = "unknown"; then
     AC_MSG_WARN([Cannot find proper types to use for getnameinfo args])
     AC_MSG_WARN([Undefining HAVE_GETNAMEINFO])
-    undefine([HAVE_GETNAMEINFO])dnl
+#undef HAVE_GETNAMEINFO
     ac_cv_func_getnameinfo="no"
   else
     gni_prev_IFS=$IFS; IFS=','