$ uname -a
Linux ridgewood 3.2.0-4-amd64 #1 SMP Debian 3.2.54-2 x86_64 GNU/Linux

x.scm:
-----
(use posix)
(define fileno (port->fileno (open-input-file "lobby.css")))
(define read (file-read fileno 95))
(pp read)
(pp (string-length (car read)))
-----


$ /usr/local/chicken-4.7.0/bin/csi -ns x.scm 
("(use awful)\n\n(enable-sxml #t)\n\n(define-page (main-page-path)\n  (lambda ()\n    \"Hello there!\"))\n"
 95)
95

-----
$ /usr/local/chicken-4.9.0/bin/csi -ns x.scm 

Error: segmentation violation

        Call history:

        <syntax>          (quote posix)
        <syntax>          (##core#quote posix)
        <syntax>          (import posix)
        <syntax>          (##core#undefined)
        <syntax>          (##core#undefined)
        <eval>    (##sys#load-library (quote posix) #f)
        <syntax>          (define fileno (port->fileno (open-input-file "lobby.css")))
        <syntax>          (##core#set! fileno (port->fileno (open-input-file "lobby.css")))
        <syntax>          (port->fileno (open-input-file "lobby.css"))
        <syntax>          (open-input-file "lobby.css")
        <eval>    (port->fileno (open-input-file "lobby.css"))
        <eval>    (open-input-file "lobby.css")
        <syntax>          (define read (file-read fileno 95))
        <syntax>          (##core#set! read (file-read fileno 95))
        <syntax>          (file-read fileno 95)
        <eval>    (file-read fileno 95) <--
-----