nginx/auto/unix
2012-06-08 09:41:55 +00:00

781 lines
20 KiB
Plaintext
Executable File

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.
NGX_USER=${NGX_USER:-nobody}
if [ -z "$NGX_GROUP" ]; then
if [ $NGX_USER = nobody ]; then
if grep nobody /etc/group 2>&1 >/dev/null; then
echo "checking for nobody group ... found"
NGX_GROUP=nobody
else
echo "checking for nobody group ... not found"
if grep nogroup /etc/group 2>&1 >/dev/null; then
echo "checking for nogroup group ... found"
NGX_GROUP=nogroup
else
echo "checking for nogroup group ... not found"
NGX_GROUP=nobody
fi
fi
else
NGX_GROUP=$NGX_USER
fi
fi
ngx_feature="poll()"
ngx_feature_name=
ngx_feature_run=no
ngx_feature_incs="#include <poll.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int n; struct pollfd pl;
pl.fd = 0;
pl.events = 0;
pl.revents = 0;
n = poll(&pl, 1, 0);
if (n == -1) return 1"
. auto/feature
if [ $ngx_found = no ]; then
EVENT_POLL=NONE
fi
ngx_feature="/dev/poll"
ngx_feature_name="NGX_HAVE_DEVPOLL"
ngx_feature_run=no
ngx_feature_incs="#include <sys/devpoll.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int n, dp; struct dvpoll dvp;
dp = 0;
dvp.dp_fds = NULL;
dvp.dp_nfds = 0;
dvp.dp_timeout = 0;
n = ioctl(dp, DP_POLL, &dvp);
if (n == -1) return 1"
. auto/feature
if [ $ngx_found = yes ]; then
CORE_SRCS="$CORE_SRCS $DEVPOLL_SRCS"
EVENT_MODULES="$EVENT_MODULES $DEVPOLL_MODULE"
EVENT_FOUND=YES
fi
if test -z "$NGX_KQUEUE_CHECKED"; then
ngx_feature="kqueue"
ngx_feature_name="NGX_HAVE_KQUEUE"
ngx_feature_run=no
ngx_feature_incs="#include <sys/event.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int kq; kq = kqueue()"
. auto/feature
if [ $ngx_found = yes ]; then
have=NGX_HAVE_CLEAR_EVENT . auto/have
EVENT_MODULES="$EVENT_MODULES $KQUEUE_MODULE"
CORE_SRCS="$CORE_SRCS $KQUEUE_SRCS"
EVENT_FOUND=YES
ngx_feature="kqueue's NOTE_LOWAT"
ngx_feature_name="NGX_HAVE_LOWAT_EVENT"
ngx_feature_run=no
ngx_feature_incs="#include <sys/event.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="struct kevent kev;
kev.fflags = NOTE_LOWAT;"
. auto/feature
ngx_feature="kqueue's EVFILT_TIMER"
ngx_feature_name="NGX_HAVE_TIMER_EVENT"
ngx_feature_run=yes
ngx_feature_incs="#include <sys/event.h>
#include <sys/time.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int kq;
struct kevent kev;
struct timespec ts;
if ((kq = kqueue()) == -1) return 1;
kev.ident = 0;
kev.filter = EVFILT_TIMER;
kev.flags = EV_ADD|EV_ENABLE;
kev.fflags = 0;
kev.data = 1000;
kev.udata = 0;
ts.tv_sec = 0;
ts.tv_nsec = 0;
if (kevent(kq, &kev, 1, &kev, 1, &ts) == -1) return 1;
if (kev.flags & EV_ERROR) return 1;"
. auto/feature
fi
fi
if [ "$NGX_SYSTEM" = "NetBSD" ]; then
# NetBSD 2.0 incompatibly defines kevent.udata as "intptr_t"
cat << END >> $NGX_AUTO_CONFIG_H
#define NGX_KQUEUE_UDATA_T
END
else
cat << END >> $NGX_AUTO_CONFIG_H
#define NGX_KQUEUE_UDATA_T (void *)
END
fi
ngx_feature="crypt()"
ngx_feature_name=
ngx_feature_run=no
ngx_feature_incs=
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="crypt(\"test\", \"salt\");"
. auto/feature
if [ $ngx_found = no ]; then
ngx_feature="crypt() in libcrypt"
ngx_feature_name=
ngx_feature_run=no
ngx_feature_incs=
ngx_feature_path=
ngx_feature_libs=-lcrypt
. auto/feature
if [ $ngx_found = yes ]; then
CRYPT_LIB="-lcrypt"
fi
fi
ngx_feature="F_READAHEAD"
ngx_feature_name="NGX_HAVE_F_READAHEAD"
ngx_feature_run=no
ngx_feature_incs="#include <fcntl.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="fcntl(0, F_READAHEAD, 1);"
. auto/feature
ngx_feature="posix_fadvise()"
ngx_feature_name="NGX_HAVE_POSIX_FADVISE"
ngx_feature_run=no
ngx_feature_incs="#include <fcntl.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="posix_fadvise(0, 0, 0, POSIX_FADV_SEQUENTIAL);"
. auto/feature
ngx_feature="O_DIRECT"
ngx_feature_name="NGX_HAVE_O_DIRECT"
ngx_feature_run=no
ngx_feature_incs="#include <fcntl.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="fcntl(0, F_SETFL, O_DIRECT);"
. auto/feature
if [ $ngx_found = yes -a "$NGX_SYSTEM" = "Linux" ]; then
have=NGX_HAVE_ALIGNED_DIRECTIO . auto/have
fi
ngx_feature="F_NOCACHE"
ngx_feature_name="NGX_HAVE_F_NOCACHE"
ngx_feature_run=no
ngx_feature_incs="#include <fcntl.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="fcntl(0, F_NOCACHE, 1);"
. auto/feature
ngx_feature="directio()"
ngx_feature_name="NGX_HAVE_DIRECTIO"
ngx_feature_run=no
ngx_feature_incs="#include <sys/types.h>
#include <sys/fcntl.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="directio(0, DIRECTIO_ON);"
. auto/feature
ngx_feature="statfs()"
ngx_feature_name="NGX_HAVE_STATFS"
ngx_feature_run=no
ngx_feature_incs="$NGX_INCLUDE_SYS_PARAM_H
$NGX_INCLUDE_SYS_MOUNT_H
$NGX_INCLUDE_SYS_VFS_H"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="struct statfs fs;
statfs(\".\", &fs);"
. auto/feature
ngx_feature="statvfs()"
ngx_feature_name="NGX_HAVE_STATVFS"
ngx_feature_run=no
ngx_feature_incs="#include <sys/types.h>
#include <sys/statvfs.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="struct statvfs fs;
statvfs(\".\", &fs);"
. auto/feature
ngx_feature="dlopen()"
ngx_feature_name=
ngx_feature_run=no
ngx_feature_incs="#include <dlfcn.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="dlopen(NULL, 0)"
. auto/feature
if [ $ngx_found != yes ]; then
ngx_feature="dlopen() in libdl"
ngx_feature_libs="-ldl"
. auto/feature
if [ $ngx_found = yes ]; then
NGX_LIBDL="-ldl"
fi
fi
ngx_feature="sched_yield()"
ngx_feature_name="NGX_HAVE_SCHED_YIELD"
ngx_feature_run=no
ngx_feature_incs="#include <sched.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="sched_yield()"
. auto/feature
if [ $ngx_found != yes ]; then
ngx_feature="sched_yield() in librt"
ngx_feature_libs="-lrt"
. auto/feature
if [ $ngx_found = yes ]; then
CORE_LIBS="$CORE_LIBS -lrt"
fi
fi
ngx_feature="SO_SETFIB"
ngx_feature_name="NGX_HAVE_SETFIB"
ngx_feature_run=no
ngx_feature_incs="#include <sys/socket.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="setsockopt(0, SOL_SOCKET, SO_SETFIB, NULL, 4)"
. auto/feature
ngx_feature="SO_ACCEPTFILTER"
ngx_feature_name="NGX_HAVE_DEFERRED_ACCEPT"
ngx_feature_run=no
ngx_feature_incs="#include <sys/socket.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="setsockopt(0, SOL_SOCKET, SO_ACCEPTFILTER, NULL, 0)"
. auto/feature
ngx_feature="TCP_DEFER_ACCEPT"
ngx_feature_name="NGX_HAVE_DEFERRED_ACCEPT"
ngx_feature_run=no
ngx_feature_incs="#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="setsockopt(0, IPPROTO_TCP, TCP_DEFER_ACCEPT, NULL, 0)"
. auto/feature
ngx_feature="TCP_KEEPIDLE, TCP_KEEPINTVL, TCP_KEEPCNT"
ngx_feature_name="NGX_HAVE_KEEPALIVE_TUNABLE"
ngx_feature_run=no
ngx_feature_incs="#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="setsockopt(0, IPPROTO_TCP, TCP_KEEPIDLE, NULL, 0);
setsockopt(0, IPPROTO_TCP, TCP_KEEPINTVL, NULL, 0);
setsockopt(0, IPPROTO_TCP, TCP_KEEPCNT, NULL, 0)"
. auto/feature
ngx_feature="TCP_INFO"
ngx_feature_name="NGX_HAVE_TCP_INFO"
ngx_feature_run=no
ngx_feature_incs="#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="socklen_t optlen = sizeof(struct tcp_info);
struct tcp_info ti;
ti.tcpi_rtt = 0;
ti.tcpi_rttvar = 0;
ti.tcpi_snd_cwnd = 0;
ti.tcpi_rcv_space = 0;
getsockopt(0, IPPROTO_TCP, TCP_INFO, &ti, &optlen)"
. auto/feature
ngx_feature="accept4()"
ngx_feature_name="NGX_HAVE_ACCEPT4"
ngx_feature_run=no
ngx_feature_incs="#include <sys/socket.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="accept4(0, NULL, NULL, SOCK_NONBLOCK)"
. auto/feature
if [ $NGX_FILE_AIO = YES ]; then
ngx_feature="kqueue AIO support"
ngx_feature_name="NGX_HAVE_FILE_AIO"
ngx_feature_run=no
ngx_feature_incs="#include <aio.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int n; struct aiocb iocb;
iocb.aio_sigevent.sigev_notify = SIGEV_KEVENT;
n = aio_read(&iocb)"
. auto/feature
if [ $ngx_found = yes ]; then
CORE_SRCS="$CORE_SRCS $FILE_AIO_SRCS"
elif [ $ngx_found = no ]; then
ngx_feature="Linux AIO support"
ngx_feature_name="NGX_HAVE_FILE_AIO"
ngx_feature_run=no
ngx_feature_incs="#include <linux/aio_abi.h>
#include <sys/syscall.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int n = SYS_eventfd;
struct iocb iocb;
iocb.aio_lio_opcode = IOCB_CMD_PREAD;
iocb.aio_flags = IOCB_FLAG_RESFD;
iocb.aio_resfd = -1;"
. auto/feature
if [ $ngx_found = yes ]; then
have=NGX_HAVE_EVENTFD . auto/have
CORE_SRCS="$CORE_SRCS $LINUX_AIO_SRCS"
else
cat << END
$0: no supported file AIO was found
Currently file AIO is supported on FreeBSD 4.3+ and Linux 2.6.22+ only
END
exit 1
fi
fi
fi
have=NGX_HAVE_UNIX_DOMAIN . auto/have
ngx_feature_libs=
# C types
ngx_type="int"; . auto/types/sizeof
ngx_type="long"; . auto/types/sizeof
ngx_type="long long"; . auto/types/sizeof
ngx_type="void *"; . auto/types/sizeof; ngx_ptr_size=$ngx_size
ngx_param=NGX_PTR_SIZE; ngx_value=$ngx_size; . auto/types/value
# POSIX types
case "$NGX_AUTO_CONFIG_H" in
/*)
NGX_INCLUDE_AUTO_CONFIG_H="#include \"$NGX_AUTO_CONFIG_H\""
;;
*)
NGX_INCLUDE_AUTO_CONFIG_H="#include \"../$NGX_AUTO_CONFIG_H\""
;;
esac
ngx_type="uint64_t"; ngx_types="u_int64_t"; . auto/types/typedef
ngx_type="sig_atomic_t"; ngx_types="int"; . auto/types/typedef
. auto/types/sizeof
ngx_param=NGX_SIG_ATOMIC_T_SIZE; ngx_value=$ngx_size; . auto/types/value
ngx_type="socklen_t"; ngx_types="int"; . auto/types/typedef
ngx_type="in_addr_t"; ngx_types="uint32_t"; . auto/types/typedef
ngx_type="in_port_t"; ngx_types="u_short"; . auto/types/typedef
ngx_type="rlim_t"; ngx_types="int"; . auto/types/typedef
. auto/types/uintptr_t
. auto/endianness
ngx_type="size_t"; . auto/types/sizeof
ngx_param=NGX_MAX_SIZE_T_VALUE; ngx_value=$ngx_max_value; . auto/types/value
ngx_param=NGX_SIZE_T_LEN; ngx_value=$ngx_max_len; . auto/types/value
ngx_type="off_t"; . auto/types/sizeof
ngx_param=NGX_MAX_OFF_T_VALUE; ngx_value=$ngx_max_value; . auto/types/value
ngx_param=NGX_OFF_T_LEN; ngx_value=$ngx_max_len; . auto/types/value
ngx_type="time_t"; . auto/types/sizeof
ngx_param=NGX_TIME_T_SIZE; ngx_value=$ngx_size; . auto/types/value
ngx_param=NGX_TIME_T_LEN; ngx_value=$ngx_max_len; . auto/types/value
# syscalls, libc calls and some features
if [ $NGX_IPV6 = YES ]; then
ngx_feature="AF_INET6"
ngx_feature_name="NGX_HAVE_INET6"
ngx_feature_run=no
ngx_feature_incs="#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="struct sockaddr_in6 sin6;
sin6.sin6_family = AF_INET6;"
. auto/feature
fi
ngx_feature="setproctitle()"
ngx_feature_name="NGX_HAVE_SETPROCTITLE"
ngx_feature_run=no
ngx_feature_incs="#include <stdlib.h>"
ngx_feature_path=
ngx_feature_libs=$NGX_SETPROCTITLE_LIB
ngx_feature_test="setproctitle(\"test\");"
. auto/feature
ngx_feature="pread()"
ngx_feature_name="NGX_HAVE_PREAD"
ngx_feature_run=no
ngx_feature_incs=
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="char buf[1]; ssize_t n; n = pread(0, buf, 1, 0);
if (n == -1) return 1"
. auto/feature
ngx_feature="pwrite()"
ngx_feature_name="NGX_HAVE_PWRITE"
ngx_feature_run=no
ngx_feature_incs=
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="char buf[1]; ssize_t n; n = pwrite(1, buf, 1, 0);
if (n == -1) return 1"
. auto/feature
ngx_feature="sys_nerr"
ngx_feature_name="NGX_SYS_NERR"
ngx_feature_run=value
ngx_feature_incs='#include <errno.h>
#include <stdio.h>'
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test='printf("%d", sys_nerr);'
. auto/feature
if [ $ngx_found = no ]; then
# Cygiwn defines _sys_nerr
ngx_feature="_sys_nerr"
ngx_feature_name="NGX_SYS_NERR"
ngx_feature_run=value
ngx_feature_incs='#include <errno.h>
#include <stdio.h>'
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test='printf("%d", _sys_nerr);'
. auto/feature
fi
if [ $ngx_found = no ]; then
# Solaris has no sys_nerr
ngx_feature='maximum errno'
ngx_feature_name=NGX_SYS_NERR
ngx_feature_run=value
ngx_feature_incs='#include <errno.h>
#include <string.h>
#include <stdio.h>'
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test='int n;
char *p;
for (n = 1; n < 1000; n++) {
errno = 0;
p = strerror(n);
if (errno == EINVAL
|| p == NULL
|| strncmp(p, "Unknown error", 13) == 0)
{
break;
}
}
printf("%d", n);'
. auto/feature
fi
ngx_feature="localtime_r()"
ngx_feature_name="NGX_HAVE_LOCALTIME_R"
ngx_feature_run=no
ngx_feature_incs="#include <time.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="struct tm t; time_t c=0; localtime_r(&c, &t)"
. auto/feature
ngx_feature="posix_memalign()"
ngx_feature_name="NGX_HAVE_POSIX_MEMALIGN"
ngx_feature_run=no
ngx_feature_incs="#include <stdlib.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="void *p; int n; n = posix_memalign(&p, 4096, 4096);
if (n != 0) return 1"
. auto/feature
ngx_feature="memalign()"
ngx_feature_name="NGX_HAVE_MEMALIGN"
ngx_feature_run=no
ngx_feature_incs="#include <stdlib.h>
#include <malloc.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="void *p; p = memalign(4096, 4096);
if (p == NULL) return 1"
. auto/feature
ngx_feature="mmap(MAP_ANON|MAP_SHARED)"
ngx_feature_name="NGX_HAVE_MAP_ANON"
ngx_feature_run=yes
ngx_feature_incs="#include <sys/mman.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="void *p;
p = mmap(NULL, 4096, PROT_READ|PROT_WRITE,
MAP_ANON|MAP_SHARED, -1, 0);
if (p == MAP_FAILED) return 1;"
. auto/feature
ngx_feature='mmap("/dev/zero", MAP_SHARED)'
ngx_feature_name="NGX_HAVE_MAP_DEVZERO"
ngx_feature_run=yes
ngx_feature_incs="#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test='void *p; int fd;
fd = open("/dev/zero", O_RDWR);
p = mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
if (p == MAP_FAILED) return 1;'
. auto/feature
ngx_feature="System V shared memory"
ngx_feature_name="NGX_HAVE_SYSVSHM"
ngx_feature_run=yes
ngx_feature_incs="#include <sys/ipc.h>
#include <sys/shm.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int id;
id = shmget(IPC_PRIVATE, 4096, (SHM_R|SHM_W|IPC_CREAT));
if (id == -1) return 1;
shmctl(id, IPC_RMID, NULL);"
. auto/feature
ngx_feature="POSIX semaphores"
ngx_feature_name="NGX_HAVE_POSIX_SEM"
ngx_feature_run=yes
ngx_feature_incs="#include <semaphore.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="sem_t sem;
if (sem_init(&sem, 1, 0) == -1) return 1;
sem_destroy(&sem);"
. auto/feature
if [ $ngx_found = no ]; then
# Linux has POSIX semaphores in libpthread
ngx_feature="POSIX semaphores in libpthread"
ngx_feature_libs=-lpthread
. auto/feature
if [ $ngx_found = yes ]; then
CORE_LIBS="$CORE_LIBS -lpthread"
fi
fi
if [ $ngx_found = no ]; then
# Solaris has POSIX semaphores in librt
ngx_feature="POSIX semaphores in librt"
ngx_feature_libs=-lrt
. auto/feature
if [ $ngx_found = yes ]; then
CORE_LIBS="$CORE_LIBS -lrt"
fi
fi
ngx_feature="struct msghdr.msg_control"
ngx_feature_name="NGX_HAVE_MSGHDR_MSG_CONTROL"
ngx_feature_run=no
ngx_feature_incs="#include <sys/socket.h>
#include <stdio.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="struct msghdr msg;
printf(\"%d\", (int) sizeof(msg.msg_control))"
. auto/feature
ngx_feature="ioctl(FIONBIO)"
ngx_feature_name="NGX_HAVE_FIONBIO"
ngx_feature_run=no
ngx_feature_incs="#include <sys/ioctl.h>
#include <stdio.h>
$NGX_INCLUDE_SYS_FILIO_H"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="int i = FIONBIO; printf(\"%d\", i)"
. auto/feature
ngx_feature="struct tm.tm_gmtoff"
ngx_feature_name="NGX_HAVE_GMTOFF"
ngx_feature_run=no
ngx_feature_incs="#include <time.h>
#include <stdio.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="struct tm tm; tm.tm_gmtoff = 0;
printf(\"%d\", (int) tm.tm_gmtoff)"
. auto/feature
ngx_feature="struct dirent.d_namlen"
ngx_feature_name="NGX_HAVE_D_NAMLEN"
ngx_feature_run=no
ngx_feature_incs="#include <dirent.h>
#include <stdio.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="struct dirent dir; dir.d_namlen = 0;
printf(\"%d\", (int) dir.d_namlen)"
. auto/feature
ngx_feature="struct dirent.d_type"
ngx_feature_name="NGX_HAVE_D_TYPE"
ngx_feature_run=no
ngx_feature_incs="#include <dirent.h>
#include <stdio.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="struct dirent dir; dir.d_type = DT_REG;
printf(\"%d\", (int) dir.d_type)"
. auto/feature
ngx_feature="sysconf(_SC_NPROCESSORS_ONLN)"
ngx_feature_name="NGX_HAVE_SC_NPROCESSORS_ONLN"
ngx_feature_run=no
ngx_feature_incs=
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="sysconf(_SC_NPROCESSORS_ONLN)"
. auto/feature
ngx_feature="openat(), fstatat()"
ngx_feature_name="NGX_HAVE_OPENAT"
ngx_feature_run=no
ngx_feature_incs="#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>"
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test="struct stat sb;
openat(AT_FDCWD, \".\", O_RDONLY|O_NOFOLLOW);
fstatat(AT_FDCWD, \".\", &sb, AT_SYMLINK_NOFOLLOW);"
. auto/feature