at some point, a perl update broke this syntax.  use a newer style that works
with at least perl-5.16.

--- a/automake.in
+++ b/automake.in
@@ -983,7 +983,7 @@ sub finish_languages
 
 	# Compute the function name of the finisher and then call it.
 	$name = 'lang_' . $lang . '_finish';
-	do $name ();
+	&$name ();
     }
 
     # If the project is entirely C++ or entirely Fortran 77, don't
@@ -1144,7 +1144,7 @@ sub handle_single_transform_list
 		# Found the language, so see what it says.
 		local ($subr) = 'lang_' . $lang . '_rewrite';
 		# Note: computed subr call.
-		local ($r) = do $subr ($base, $extension);
+		local ($r) = &$subr ($base, $extension);
 		# Skip this entry if we were asked not to process it.
 		next if ! $r;