Fix some compilation issues on modern macOS systems (#6709)

* Fix various compiler warnings generated by Apple clang 15, and workaround some boost 1.8 bugs

* Fix formatting.

src/extractor/intersection/coordinate_extractor.cpp

@@ -887,19 +887,21 @@ CoordinateExtractor::PrepareLengthCache(const std::vector<util::Coordinate> &coo
     segment_distances.push_back(0);
     // sentinel
     // NOLINTNEXTLINE(bugprone-unused-return-value)
-    std::find_if(std::next(std::begin(coordinates)),
-                 std::end(coordinates),
-                 [last_coordinate = coordinates.front(),
-                  limit,
-                  &segment_distances,
-                  accumulated_distance = 0.](const util::Coordinate current_coordinate) mutable {
-                     const auto distance = util::coordinate_calculation::greatCircleDistance(
-                         last_coordinate, current_coordinate);
-                     accumulated_distance += distance;
-                     last_coordinate = current_coordinate;
-                     segment_distances.push_back(distance);
-                     return accumulated_distance >= limit;
-                 });
+    // We're only interested in the side effect of the lambda, not the return value
+    [[maybe_unused]] auto _ = std::find_if(
+        std::next(std::begin(coordinates)),
+        std::end(coordinates),
+        [last_coordinate = coordinates.front(),
+         limit,
+         &segment_distances,
+         accumulated_distance = 0.](const util::Coordinate current_coordinate) mutable {
+            const auto distance = util::coordinate_calculation::greatCircleDistance(
+                last_coordinate, current_coordinate);
+            accumulated_distance += distance;
+            last_coordinate = current_coordinate;
+            segment_distances.push_back(distance);
+            return accumulated_distance >= limit;
+        });
     return segment_distances;
 }
 
@@ -1090,7 +1092,8 @@ CoordinateExtractor::SampleCoordinates(const std::vector<util::Coordinate> &coor
     };
 
     // misuse of adjacent_find. Loop over coordinates, until a total sample length is reached
-    std::adjacent_find(coordinates.begin(), coordinates.end(), add_samples_until_length_limit);
+    [[maybe_unused]] auto _ =
+        std::adjacent_find(coordinates.begin(), coordinates.end(), add_samples_until_length_limit);
 
     return sampled_coordinates;
 }

src/partitioner/dinic_max_flow.cpp

@@ -195,7 +195,9 @@ std::size_t DinicMaxFlow::BlockingFlow(FlowEdges &flow,
         };
 
         // augment all adjacent edges
-        std::adjacent_find(path.begin(), path.end(), augment_one);
+        // We're only interested in the side-effect of the augment_one function, the return
+        // value is ignored
+        [[maybe_unused]] auto _ = std::adjacent_find(path.begin(), path.end(), augment_one);
     };
 
     const auto augment_all_paths = [&](const NodeID sink_node_id) {

src/util/coordinate_calculation.cpp

@@ -323,7 +323,8 @@ double findClosestDistance(const std::vector<Coordinate> &lhs, const std::vector
         return false;
     };
     // NOLINTNEXTLINE(bugprone-unused-return-value)
-    std::find_if(std::begin(lhs), std::end(lhs), compute_minimum_distance_in_rhs);
+    [[maybe_unused]] auto _ =
+        std::find_if(std::begin(lhs), std::end(lhs), compute_minimum_distance_in_rhs);
     return current_min;
 }