Allow configuring iOS build with CMake (#3234)

platform/darwin/core/nsthread.mm

@@ -0,0 +1,52 @@
+#import <Foundation/Foundation.h>
+
+#include <mbgl/util/logging.hpp>
+#include <mbgl/util/platform.hpp>
+#include <mbgl/platform/thread.hpp>
+
+#include <pthread.h>
+
+namespace mbgl {
+namespace platform {
+
+std::string getCurrentThreadName() {
+    char name[32] = "unknown";
+    pthread_getname_np(pthread_self(), name, sizeof(name));
+
+    return name;
+}
+
+void setCurrentThreadName(const std::string& name) {
+    std::string qualifiedName = "org.maplibre.mbgl." + name;
+    pthread_setname_np(qualifiedName.c_str());
+}
+
+void makeThreadLowPriority() {
+    [NSThread currentThread].qualityOfService = NSQualityOfServiceUtility;
+}
+
+void setCurrentThreadPriority(double priority) {
+    if (priority > 1.0 || priority < 0.0) {
+        Log::Warning(Event::General, "Invalid thread priority was provided");
+        return;
+    }
+
+    if (priority < 0.25) {
+        [NSThread currentThread].qualityOfService = NSQualityOfServiceBackground;
+    } else if (priority < 0.5) {
+        [NSThread currentThread].qualityOfService = NSQualityOfServiceUtility;
+    } else if (priority < 0.75) {
+        [NSThread currentThread].qualityOfService = NSQualityOfServiceUserInitiated;
+    } else {
+        [NSThread currentThread].qualityOfService = NSQualityOfServiceUserInteractive;
+    }
+}
+
+void attachThread() {
+}
+
+void detachThread() {
+}
+
+}
+}