Report 'haiku' as a platform, and don't bind to :: on it, because that doesn't seem to be working.

git-svn-id: https://www.unprompted.com/svn/projects/tildefriends/trunk@4587 ed5197a5-7fde-0310-b194-c3ffbd925b24

src/task.c

@@ -715,6 +715,8 @@ static JSValue _tf_task_platform(JSContext* context, JSValueConst this_val, int
 #endif
 #elif defined(__linux__)
 	return JS_NewString(context, "linux");
+#elif defined(__HAIKU__)
+	return JS_NewString(context, "haiku");
 #else
 	return JS_NewString(context, "other");
 #endif