Added operator less for class argidx_and_tokennamet.

Author: marek-trtik

src/taint-slicer/propagation_chains.h

@@ -49,6 +49,12 @@ class argidx_and_tokennamet
   int argidx;
   taint_tokent::namet tokenname;
 };
+inline bool operator<(
+  const argidx_and_tokennamet &l, const argidx_and_tokennamet &r)
+{
+  return std::make_pair(l.get_argidx(), l.get_token_name())<
+         std::make_pair(r.get_argidx(), r.get_token_name());
+}
 std::ostream &operator<<(std::ostream &ostr, const argidx_and_tokennamet &atp);
 
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