--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2011-04-25  Jim Meyering  <meyering@redhat.com>
+
+	maint.mk: makefile_at_at_check extend and clean up
+	* top/maint.mk (sc_makefile_at_at_check): Check *.mk files
+	in addition to */Makefile.am.
+	Exempt legitimate uses of @VAR@ notation, e.g.,
+	MAKEINFO = env LANG= LC_MESSAGES= LC_ALL= LANGUAGE= @MAKEINFO@
+	Remove obsolete coreutils-specific comment.
+	Prompted by discussion here:
+	http://thread.gmane.org/gmane.comp.lib.gnulib.bugs/26074
+
 2011-04-24  Paul Eggert  <eggert@cs.ucla.edu>
 
 	strtoul: remove dependency on strtol

--- a/top/maint.mk
+++ b/top/maint.mk
@@ -942,16 +942,23 @@
 # Ensure that we use only the standard $(VAR) notation,
 # not @...@ in Makefile.am, now that we can rely on automake
 # to emit a definition for each substituted variable.
-# We use perl rather than "grep -nE ..." to exempt a single
-# use of an @...@-delimited variable name in src/Makefile.am.
+# However, there is still one case in which @VAR@ use is not just
+# legitimate, but actually required: when augmenting an automake-defined
+# variable with a prefix.  For example, gettext uses this:
+# MAKEINFO = env LANG= LC_MESSAGES= LC_ALL= LANGUAGE= @MAKEINFO@
+# otherwise, makeinfo would put German or French (current locale)
+# navigation hints in the otherwise-English documentation.
+#
 # Allow the package to add exceptions via a hook in cfg.mk;
 # for example, @PRAGMA_SYSTEM_HEADER@ can be permitted by
 # setting this to ' && !/PRAGMA_SYSTEM_HEADER/'.
 _makefile_at_at_check_exceptions ?=
 sc_makefile_at_at_check:
-	@perl -ne '/\@[A-Z_0-9]+\@/'$(_makefile_at_at_check_exceptions)	\
+	@perl -ne '/\@[A-Z_0-9]+\@/'					\
+          -e ' && !/([A-Z_0-9]+)\s+=.*\@\1\@$$/'			\
+          -e ''$(_makefile_at_at_check_exceptions)			\
 	  -e 'and (print "$$ARGV:$$.: $$_"), $$m=1; END {exit !$$m}'	\
-	    $$($(VC_LIST_EXCEPT) | grep -E '(^|/)Makefile\.am$$')	\
+	    $$($(VC_LIST_EXCEPT) | grep -E '(^|/)(Makefile\.am|[^/]+\.mk)$$') \
 	  && { echo '$(ME): use $$(...), not @...@' 1>&2; exit 1; } || :
 
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