Sun studio workaround for callback testcase

Examples/test-suite/callback.i

@@ -57,6 +57,22 @@
     return pf(a);
   }
 
+#if defined(__SUNPRO_CC)
+// workaround for: Error: Could not find a match for foobar_T<T>(int, extern "C" int(*)(int)).
+  extern "C" {
+    typedef int (*foobar_int_int)(int a);
+    typedef double (*foobar_double_double)(double a);
+  };
+  template <class T>
+  int foobar_T(int a, foobar_int_int pf) {
+    return pf(a);
+  }
+  template <class T>
+  double foobar_T(double a, foobar_double_double pf) {
+    return pf(a);
+  }
+#endif
+
   template <class T>
   const T& ident(const T& x) {
     return x;