The attached patch fixes tcflush() and tcdrain() in the termios
package. These functions would call the fo_getinfo() function of the
file system code with a 0 length (the length value is unused). The
fo_getinfo() code in devfs.cxx would then convert this into a non-NULL
pointer to a value of 0 when calling cyg_io_get_config(). This
combination (non-NULL pointer to 0 value) is a special case in
cyg_io_get_config() used to determine if the get_config method is
available for the device. It always returns success (ENOERR) when the
method is defined and does nothing.
By changing the length value passed to the fo_getinfo() function to a
non-zero value, this avoids this.