ExtUnix.ConfigCompile-time configuration information
val have :
[< `ATFILE
| `CHROOT
| `CLEARENV
| `CTERMID
| `DIRFD
| `ENDIAN
| `EVENTFD
| `EXECINFO
| `FADVISE
| `FALLOCATE
| `FCNTL
| `FDATASYNC
| `FEXECVE
| `FSTATVFS
| `FSYNC
| `GETTID
| `IFADDRS
| `INET_NTOA
| `INET_NTOP
| `MALLOC_INFO
| `MALLOC_STATS
| `MCHECK
| `MEMALIGN
| `MKDTEMP
| `MKOSTEMPS
| `MKSTEMPS
| `MLOCKALL
| `MOUNT
| `PGID
| `POLL
| `PREAD
| `PTRACE
| `PTS
| `PWRITE
| `READ
| `READ_CREDENTIALS
| `REALPATH
| `RESOURCE
| `SENDMSG
| `SETENV
| `SETRESUID
| `SETREUID
| `SIGNALFD
| `SIOCGIFCONF
| `SOCKOPT
| `SO_REUSEPORT
| `SPLICE
| `STATVFS
| `STRPTIME
| `STRTIME
| `SYNC
| `SYNCFS
| `SYSCONF
| `SYSINFO
| `SYSLOG
| `TCPGRP
| `TCP_KEEPCNT
| `TCP_KEEPIDLE
| `TCP_KEEPINTVL
| `TEE
| `TIMEGM
| `TIMEZONE
| `TTYNAME
| `TTY_IOCTL
| `UNAME
| `UNSHARE
| `VMSPLICE
| `WRITE ] ->
bool