new behavior in M4 1.4.5 breaks autoconf "make check"

[Paul Eggert]

Apparently a post-1.4.4b change to M4 changed one of its diagnostics?
Anyway, the new diagnostic in M4 1.4.5 breaks Autoconf's "make check".
I assume this change is permanent so I have installed the following
into Autoconf.

2006-07-17  Paul Eggert  <address@hidden>

        * NEWS: Recommend M4 1.4.5.
        * tests/tools.at (autom4te cache): Update wording of diagnostic
        to match M4 1.4.5.

--- NEWS        7 Jul 2006 14:21:57 -0000       1.391
+++ NEWS        17 Jul 2006 17:29:57 -0000
@@ -1,5 +1,8 @@
 * Major changes in Autoconf 2.60a
 
+** GNU M4 1.4.5 or later is now recommended.  At least one "make check"
+  test fails with earlier versions of M4.
+
 ** The functionality of the undocumented _AC_COMPUTE_INT is now provided
   by a public and documented macro, AC_COMPUTE_INT.  The parameters to the
   two macros are different, so autoupdate will not change the old private name
--- tests/tools.at      20 Jun 2006 05:37:43 -0000      1.89
+++ tests/tools.at      17 Jul 2006 17:29:57 -0000
@@ -101,7 +101,7 @@ AT_CHECK_M4SUGAR
 mkdir sub
 mv foo sub
 AT_CHECK_M4SUGAR([], [1], [],
-[m4: script.4s: 1: Cannot open foo: No such file or directory
+[m4: script.4s: 1: cannot open `foo': No such file or directory
 autom4te: m4 failed with exit status: 1
 ])