Minor corrections - lib_screen.c

[Philippe Blain]

>From Philippe Blain, Bordeaux, FRANCE.
My old computer: P133 - 8,4 Go - 32 Mo Red Hat Linux 7.0

To maintainers of 'ncurses'.(and to Mr Dickey)
Subject: Corrections for ncurses-5.2-20020817+

Here are some problems I found:

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File : ncurses/base/lib_screen.c

Function : getwin() - Clearing errors indicator before testing
    .................
    T((T_CALLED("getwin(%p)"), filep));

==> clearerr(filep);
    (void) fread(&tmp, sizeof(WINDOW), 1, filep);
    if (ferror(filep))
    returnWin(0);
    .................

Function : putwin() - Idem
    .................
    T((T_CALLED("putwin(%p,%p)"), win, filep));

    if (win) {
==>     clearerr(filep);
        (void) fwrite(win, sizeof(WINDOW), 1, filep);
        if (ferror(filep))
            returnCode(code);
    .................

Function : scr_set() - Forgot something in correcting bugzilla #68199

NCURSES_EXPORT(int) scr_set(const char *file)
{
    T((T_CALLED("scr_set(%s)"), _nc_visbuf(file)));

    if (scr_init(file) == ERR) {
        returnCode(ERR);
    } else {
        delwin(newscr);
==>     SP->_newscr = newscr = dupwin(curscr);
        returnCode(OK);
    }
}

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- Philippe