diff --git a/tests/local.at b/tests/local.at
index 97a1e1d..47501bf 100644
--- a/tests/local.at
+++ b/tests/local.at
@@ -113,13 +113,14 @@ m4_define([AT_CHECK_M4],
 [AT_CHECK([$1], [$2], [$3],
           m4_case([$4], [], [], [ignore], [ignore], [stderr]))
 m4_case([$4], [], [], [ignore], [],
-[AT_CHECK([[sed 's/^[^:]*m4[-.ex0-9]*: *\([^:]*:\) *\([0-9][0-9]*: \)/m4:\1\2/
+[AT_CHECK([[mv stderr stderr-raw &&
+   sed 's/^[^:]*m4[-.ex0-9]*: *\([^:]*:\) *\([0-9][0-9]*: \)/m4:\1\2/
 	s/^\([^:]*:\) *\([0-9][0-9]*:\)[^:]*m4[-.ex0-9]*: /m4:\1\2 /
 	s/: C\(annot open \)\([^`:]*\):/: c\1`\2'\'':/
 	s/: include:\( cannot open\)/:\1/
 	s/^autom4te: [^ ]*m4[.ex]* /autom4te: m4 /
 	s/ (E[A-Z]*)$//
-    ' stderr >&2]], [0], [], [$4])])
+    ' stderr-raw >&2]], [0], [], [$4])])
 ])
 
 # AT_CHECK_AUTOM4TE(FLAGS, [EXIT-STATUS = 0], STDOUT, STDERR)