diff --git a/ares/m4/reentrant.m4 b/ares/m4/reentrant.m4
index 62938d8370ecc7a26829310c8173db85f27bcb3e..bfe68cb40633a132e50ad681319ceaa460ed7bcd 100644
--- a/ares/m4/reentrant.m4
+++ b/ares/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
 ])
 
diff --git a/m4/reentrant.m4 b/m4/reentrant.m4
index 8435e281e1d19a04c41c0f38c2cb4956f6b27fa8..e5af41e97cf6b78513dd87041be41a1772ee4ed5 100644
--- a/m4/reentrant.m4
+++ b/m4/reentrant.m4
@@ -376,9 +376,9 @@ AC_DEFUN([CURL_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
 ])