devel/cdecl: update to 6.10

Added auto_type
Added GNU C's auto_type.

Fixed long long C version
The long long type was incorrectly allowed in C89; it wasn't added until C99.

Added pthread.h, threads.h, and C++ thread types
The types pthread_t, pthread_barrier_t, pthread_barrierattr_t, pthread_cond_t, pthread_condattr_t, pthread_mutex_t, pthread_mutexattr_t, pthread_once_t, pthread_rwlock_t, pthread_rwlockattr_t, and pthread_spinlock_t from <pthread.h> (POSIX); the types thrd_t, cnd_t, mtx_t, once_flag, thrd_start_t, tss_dtor_t, and tss_t from <thread.h> (C11); and std::thread (C++11) and std::jthread (C++20) from <thread> to the set of predefined types.