Merging r4130, r4131, r4135: Linux AIO related fixes: *) Fixing Linux AIO syscalls return value handling: syscall(2) uses usual libc convention, it returns -1 on error and sets errno. Obsolete _syscall(2) returns negative value of error. *) Fixing Linux AIO initiatialization: AIO operations are disabled if kernel does not support them. Previously worker just exited. *) The "worker_aio_requests" directive. The default value is 32 AIO simultaneous requests per worker. Previously they were hardcoded to 1024, and it was too large, since Linux allocated them early on io_setup(), but not on request itself. So with default value of /proc/sys/fs/aio-max-nr equal to 65536 only 64 worker processes could be run simultaneously. 32 AIO requests are enough for modern disks even if server runs only 1 worker.

# Copyright (C) Igor Sysoev


echo $ngx_n "checking for $ngx_lib ...$ngx_c"

cat << END >> $NGX_AUTOCONF_ERR

----------------------------------------
checking for $ngx_lib

END

ngx_found=no

cat << END > $NGX_AUTOTEST.c

$ngx_lib_incs

int main() {
    $ngx_lib_test;
    return 0;
}


eval "$CC $cc_test_flags $ngx_lib_cflags \
     -o $NGX_AUTOTEST $NGX_AUTOTEST.c $ngx_libs \
     >> $NGX_ERR 2>&1"

if [ -x $NGX_AUTOTEST ]; then
    echo " found"

    ngx_found=yes

else
    echo " not found"
fi

rm $NGX_AUTOTEST*