Made the lib work with -fno-exceptions (at least for now).

source/mijin/async/coroutine.hpp

@@ -27,6 +27,18 @@
 #include "../debug/stacktrace.hpp"
 #endif
 
+#if !defined(MIJIN_COROUTINE_ENABLE_EXCEPTION_HANDLING)
+#   define MIJIN_COROUTINE_ENABLE_EXCEPTION_HANDLING MIJIN_ENABLE_EXCEPTIONS
+#elif !__cpp_exceptions
+#   error "Coroutine exception handling enabled, but exceptions are disabled."
+#endif
+
+#if !defined(MIJIN_COROUTINE_ENABLE_CANCEL)
+#   define MIJIN_COROUTINE_ENABLE_CANCEL MIJIN_ENABLE_EXCEPTIONS
+#elif !__cpp_exceptions
+#   error "Cancelling tasks requires exceptions to be anbled."
+#endif
+
 namespace mijin
 {
 
@@ -56,7 +68,9 @@ class TaskLoop;
 template<typename TResult = void>
 class TaskBase;
 
+#if MIJIN_COROUTINE_ENABLE_CANCEL
 struct TaskCancelled : std::exception {};
+#endif
 
 namespace impl
 {
@@ -585,10 +599,12 @@ extern thread_local TaskLoop::StoredTask* gCurrentTask;
 
 inline void throwIfCancelled()
 {
+#if MIJIN_COROUTINE_ENABLE_CANCEL
     if (gCurrentTask->task->sharedState()->cancelled_)
     {
         throw TaskCancelled();
     }
+#endif
 }
 }
 
@@ -657,13 +673,16 @@ inline TaskStatus TaskLoop::tickTask(StoredTask& task)
     while (status == TaskStatus::RUNNING);
     impl::gCurrentTask = nullptr;
 
+#if MIJIN_COROUTINE_ENABLE_EXCEPTION_HANDLING
     if (task.task && task.task->exception())
     {
         try
         {
             std::rethrow_exception(task.task->exception());
         }
+#if MIJIN_COROUTINE_ENABLE_CANCEL
         catch(TaskCancelled&) {} // ignore those
+#endif
         catch(...)
         {
             if (uncaughtExceptionHandler_)
@@ -679,6 +698,7 @@ inline TaskStatus TaskLoop::tickTask(StoredTask& task)
         // TODO: handle the exception somehow, others may be waiting
         return TaskStatus::FINISHED;
     }
+#endif // MIJIN_COROUTINE_ENABLE_EXCEPTION_HANDLING
     if (status == TaskStatus::YIELDED || status == TaskStatus::FINISHED)
     {
         task.setFuture(task);