change dispatch queue priority

Makefile

@@ -1,7 +1,7 @@
 DESTDIR=
 PREFIX=/usr/local
 CXX=clang++
-LD=`xcrun -f clang++`
+LD=$(shell xcrun -f clang++)
 CXXFLAGS=-O2 -std=c++17
 LDFLAGS=-std=c++17
 

src/ParallelForEach.h

@@ -10,7 +10,7 @@ inline void parallel_for_each(It a, It b, F&& f)
     using data_t = std::pair<It, F>;
     data_t helper = data_t(a, std::forward<F>(f));
     dispatch_apply_f(count,
-                     dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),
+                     dispatch_get_global_queue(QOS_CLASS_USER_INTERACTIVE, 0),
                      &helper,
                      [](void* ctx, size_t cnt) {
         data_t* d = static_cast<data_t*>(ctx);