diff --git a/m4/reentrant.m4 b/m4/reentrant.m4
index 62938d83..bfe68cb4 100644
--- a/m4/reentrant.m4
+++ b/m4/reentrant.m4
@@ -354,9 +354,9 @@ AC_DEFUN([CARES_CONFIGURE_FROM_NOW_ON_WITH_REENTRANT], [
 AC_DEFINE(NEED_REENTRANT, 1,
   [Define to 1 if _REENTRANT preprocessor symbol must be defined.])
 cat >>confdefs.h <<_ACEOF
-[@%:@ifndef _REENTRANT
-@%:@ define _REENTRANT
-@%:@endif]
+[#ifndef _REENTRANT
+# define _REENTRANT
+#endif]
 _ACEOF
 ])