do not start additional thread if lyrics are available locally

src/ncmpcpp.h

@@ -38,7 +38,7 @@
 #else
 # define pthread_mutex_lock(x);
 # define pthread_mutex_unlock(x);
-# define pthread_exit(x) return 0;
+# define pthread_exit(x) return (x)
 #endif // HAVE_PTHREAD_H
 
 using namespace NCurses;