Migrate to modern TBB version (#6300)

src/customize/customizer.cpp

@@ -21,11 +21,7 @@
 
 #include <boost/assert.hpp>
 
-#if TBB_VERSION_MAJOR == 2020
 #include <tbb/global_control.h>
-#else
-#include <tbb/task_scheduler_init.h>
-#endif
 
 namespace osrm
 {
@@ -122,13 +118,8 @@ std::vector<CellMetric> customizeFilteredMetrics(const partitioner::MultiLevelEd
 
 int Customizer::Run(const CustomizationConfig &config)
 {
-#if TBB_VERSION_MAJOR == 2020
     tbb::global_control gc(tbb::global_control::max_allowed_parallelism,
                            config.requested_num_threads);
-#else
-    tbb::task_scheduler_init init(config.requested_num_threads);
-    BOOST_ASSERT(init.is_active());
-#endif
 
     TIMER_START(loading_data);