Reference for unit 'unixtype': Constants

`ARG_MAX`		Max number of command-line arguments.
`NAME_MAX`		Max length (in bytes) of filename
`PATH_MAX`		Max length (in bytes) of pathname
`Prio_PGrp`		#rtl.baseunix.fpGetPriority option: Get process group priority.
`Prio_Process`		#rtl.baseunix.fpGetPriority option: Get process priority.
`Prio_User`		#rtl.baseunix.fpGetPriority option: Get user priority.
`pthreadrwlocksize`		Size of `pthread_rwlock_t` _data structure
`SIG_MAXSIG`		Maximum signal number.
`SYS_NMLN`		Max system namelength
`_PTHREAD_MUTEX_ADAPTIVE_NP`		Mutex options:
`_PTHREAD_MUTEX_DEFAULT`		Mutex options:
`_PTHREAD_MUTEX_ERRORCHECK`		Mutex options:
`_PTHREAD_MUTEX_ERRORCHECK_NP`		Mutex options: double lock returns an error code.
`_PTHREAD_MUTEX_FAST_NP`		Mutex options: Fast mutex
`_PTHREAD_MUTEX_NORMAL`		Mutex options:
`_PTHREAD_MUTEX_RECURSIVE`		Mutex options:
`_PTHREAD_MUTEX_RECURSIVE_NP`		Mutex options: recursive mutex
`_PTHREAD_MUTEX_TIMED_NP`		Mutex options: ?