--- cool.flex	2011-06-18 03:22:02.000000000 +0000
+++ cool.flex.work	2020-12-19 22:43:35.902153646 +0000
@@ -12,6 +12,17 @@
 #include <stringtab.h>
 #include <utilities.h>
 
+/* This is a hack to
+ * a) satisfy the cool compiler which expects yylex to be named cool_yylex (see below)
+ * b) satisfy libfl > 2.5.39 which expects a yylex symbol
+ * c) fix mangling errors of yylex when compiled with a c++ compiler
+ * d) be as non-invasive as possible to the existing assignment code
+ */
+extern int cool_yylex();
+extern "C" {
+  int (&yylex) (void) = cool_yylex;
+}
+
 /* The compiler assumes these identifiers. */
 #define yylval cool_yylval
 #define yylex  cool_yylex