Update for newer C++.

dep/alphanum/alphanum.h

@@ -295,7 +295,7 @@ namespace doj
      implement "std::ostream operator<< (std::ostream&, const Ty&)".
   */
   template<class Ty>
-  struct alphanum_less : public std::binary_function<Ty, Ty, bool>
+  struct alphanum_less
   {
     bool operator()(const Ty& left, const Ty& right) const
     {

dep/alphanum/build.py

@@ -0,0 +1,8 @@
+from build.c import clibrary
+
+clibrary(
+    name="alphanum",
+    srcs=[],
+    hdrs={"dep/alphanum/alphanum.h": "./alphanum.h"},
+)
+