--- autoconf-2.69/bin/autoscan.in.old	2012-04-25 02:37:26.000000000 +0000
+++ autoconf-2.69/bin/autoscan.in	2017-08-03 23:59:38.720214631 +0000
@@ -358,7 +358,7 @@
     {
       # Strip out comments and variable references.
       s/#.*//;
-      s/\${[^\}]*}//g;
+      s/\$\{[^\}]*\}//g;
       s/@[^@]*@//g;
 
       # Tokens in the code.