Dejagnu not work with STDIN==/dev/null

Hi,

make check </den/null failed with follow message: (w/o /dev/null all 
ok). It prevent using dejagnu in autobuilder chroots. 

Using /usr/src/RPM/BUILD/dejagnu-1.4.3/testsuite/config/default.exp as 
tool-and-target-specific interface file.
Running /usr/src/RPM/BUILD/dejagnu-1.4.3/testsuite/libdejagnu/tunit.exp 
...
send: spawn id exp0 not open
    while executing
"send_user "$message\n""
    ("default" arm line 2)
    invoked from within
"case "$firstword" in {
        {"PASS:" "XFAIL:" "KFAIL:" "UNRESOLVED:" "UNSUPPORTED:" 
"UNTESTED:"} {
            if $all_flag {
                send_user "$message\n"
                return "..."
    (procedure "clone_output" line 10)
    invoked from within
"clone_output "Running $test_file_name ...""
    (procedure "runtest" line 9)
    invoked from within
"runtest $test_name"
    ("foreach" body line 42)
    invoked from within
"foreach test_name [lsort [find ${dir} *.exp]] {
                        if { ${test_name} == "" } {
                            continue

And yet more....

Reproduceable in Altlinux and Debian for both dejagnu 1.4.2 and 1.4.3.

PS Also please add option fo use pipes instead of pty - for use dejagnu 
in autobuilder chroots (w/o /proc and /dev/pts)