wget: check chunk length for overflowing off_t

function                                             old     new   delta
retrieve_file_data                                   428     465     +37
wget_main                                           2386    2389      +3
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(add/remove: 0/0 grow/shrink: 2/0 up/down: 40/0)               Total: 40 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
1 file changed