head: support -n -NUM and -c -NUM

function                                             old     new   delta
head_main                                            406     832    +426
packed_usage                                       29234   29252     +18
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(add/remove: 0/0 grow/shrink: 2/0 up/down: 444/0)             Total: 444 bytes

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