From the Perl Cookbook "solution" at www.perl.com:

    require 'sys/ioctl.ph';
    die "no TIOCSTI" unless defined &TIOCSTI;
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Of course, it also says that

    Since sys/ioctl.h translation is so dodgy, you'll
    probably have to run this C program to get your
    TIOCSTI value.

        % cat > tio.c <<EOF && cc tio.c && a.out
        main() { printf("%#08x\n", TIOCSTI); }
        EOF
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