integrating c++17 fixes from #959 (ref:https://github.com/flann-lib/flann/pull/392), fixed pop_t error (b6e37553de)

corelib/src/rtflann/algorithms/dist.h

@@ -477,6 +477,10 @@ struct HammingPopcnt
     ResultType operator()(Iterator1 a, Iterator2 b, size_t size, ResultType /*worst_dist*/ = -1) const
     {
         ResultType result = 0;
+
+        //for portability just use unsigned long -- and use the __builtin_popcountll (see docs for __builtin_popcountll)
+        typedef unsigned long long pop_t;
+
 #if __GNUC__
 #if ANDROID && HAVE_NEON
         static uint64_t features = android_getCpuFeatures();

corelib/src/rtflann/algorithms/kdtree_index.h

@@ -37,6 +37,7 @@
 #include <cstring>
 #include <stdarg.h>
 #include <cmath>
+#include <random>
 
 #include "rtflann/general.h"
 #include "rtflann/algorithms/nn_index.h"
@@ -677,7 +678,9 @@ protected:
         /* Construct the randomized trees. */
         for (int i = 0; i < trees_; i++) {
             /* Randomize the order of vectors to allow for unbiased sampling. */
-            std::random_shuffle(ind.begin(), ind.end());
+            std::random_device rd;
+            std::mt19937 g(rd());
+            std::shuffle(ind.begin(), ind.end(), g);
             tree_roots_[i] = divideTree(&ind[0], int(size_) );
         }
         delete[] mean_;