diff -ru automake-1.11.6/automake.in automake-1.11.6-new/automake.in
--- automake-1.11.6/automake.in	2012-07-09 08:39:57.000000000 -0700
+++ automake-1.11.6-new/automake.in	2017-06-06 11:20:30.047651821 -0700
@@ -4156,7 +4156,7 @@
 sub substitute_ac_subst_variables ($)
 {
   my ($text) = @_;
-  $text =~ s/\${([^ \t=:+{}]+)}/&substitute_ac_subst_variables_worker ($1)/ge;
+  $text =~ s/\$[{]([^ \t=:+{}]+)}/substitute_ac_subst_variables_worker ($1)/ge;
   return $text;
 }