Remove lambda and pass free function directly.

Refs #17913

Framework/HistogramData/src/Interpolate.cpp

@@ -124,15 +124,14 @@ void interpolateYCSplineInplace(const Histogram &input, const size_t stepSize,
   // Manage gsl memory with unique_ptrs
   using gsl_spline_uptr = std::unique_ptr<gsl_spline, void (*)(gsl_spline *)>;
   auto spline = gsl_spline_uptr(gsl_spline_alloc(gsl_interp_cspline, ncalc),
-                                [](gsl_spline *sp) { gsl_spline_free(sp); });
+                                gsl_spline_free);
   // Compute spline
   gsl_spline_init(spline.get(), xc.data(), yc.data(), ncalc);
   // Evaluate each point for the full range
   using gsl_interp_accel_uptr =
       std::unique_ptr<gsl_interp_accel, void (*)(gsl_interp_accel *)>;
-  auto lookupTable = gsl_interp_accel_uptr(
-      gsl_interp_accel_alloc(),
-      [](gsl_interp_accel *acc) { gsl_interp_accel_free(acc); });
+  auto lookupTable =
+      gsl_interp_accel_uptr(gsl_interp_accel_alloc(), gsl_interp_accel_free);
   for (size_t i = 0; i < nypts; ++i) {
     ynew[i] = gsl_spline_eval(spline.get(), xold[i], lookupTable.get());
   }