Deallocates a specified conversion descriptor and the resources
    allocated to the descriptor.
    Format
      #include  <iconv.h>
      int iconv_close  (iconv_t cd);
1 – Argument
 cd
    The conversion descriptor to be deallocated. A conversion
    descriptor is returned by a successful call to iconv_open.
2 – Return Values
    0                  Indicates that the conversion descriptor was
                       successfully deallocated.
    -1                 Indicates an error occurred. The function sets
                       errno to one of the following:
                       o  EBADF - The cd argument is not a valid
                          conversion descriptor.
                       o  EVMSERR - Nontranslatable OpenVMS error
                          occur. vaxc$errno contains the VMS error
                          code.