diff --git a/support/fatal_error.m4 b/support/fatal_error.m4
index 8b01dc263..edf39ee70 100644
--- a/support/fatal_error.m4
+++ b/support/fatal_error.m4
@@ -1,2 +1,4 @@
-ifdef(`m4_werror',`errprint(__file__: Notice: Treating warnings as errors.__endline__)')
-ifdef(`m4_fatal_error',`m4exit(`1')')
+ifdef(`m4_fatal_error',`
+    ifdef(`m4_werror',`errprint(__file__: Notice: Treating warnings as errors.__endline__)')
+    m4exit(`1')
+')