od: get rid of (almost all) statics

od: get rid of (almost all) statics

function                                             old     new   delta
od_main                                             2565    2600     +35
check_and_close                                      113     115      +2
static.prev_pair_equal                                 1       -      -1
static.first                                           1       -      -1
exit_code                                              1       -      -1
string_min                                             4       -      -4
n_specs                                                4       -      -4
in_stream                                              4       -      -4
format_address                                         4       -      -4
file_list                                              4       -      -4
bytes_per_block                                        4       -      -4
get_lcm                                              120     115      -5
pseudo_offset                                          8       -      -8
------------------------------------------------------------------------------
(add/remove: 0/10 grow/shrink: 2/1 up/down: 37/-40)            Total: -3 bytes
   text	   data	    bss	    dec	    hex	filename
 938487	    932	  17392	 956811	  e998b	busybox_old
 938519	    924	  17360	 956803	  e9983	busybox_unstripped

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