brctl: eliminate stray data object

brctl: eliminate stray data object
brctl: use constant fd to reduce parameter passing
runsvdir: do not use data/bss
od: reuse bb_argv_dash
last: do not go into endless loop on read error
mount: make it not fail scripts/find_bad_common_bufsiz check
dc: add INIT_G() (no-op for dc, but we want uniform usage of "G trick")

function                                             old     new   delta
runsvdir_main                                       1646    1672     +26
set_pgrp                                               1       -      -1
exitsoon                                               1       -      -1
check                                                679     678      -1
svnum                                                  4       -      -4
svdir                                                  4       -      -4
sv                                                     4       -      -4
stamplog                                               4       -      -4
rploglen                                               4       -      -4
rplog                                                  4       -      -4
mount_main                                           995     988      -7
static.default_file_list                               8       -      -8
pfd                                                    8       -      -8
logpipe                                                8       -      -8
static.info                                           20       -     -20
brctl_main                                           767     739     -28
------------------------------------------------------------------------------
(add/remove: 0/12 grow/shrink: 1/3 up/down: 26/-106)          Total: -80 bytes
   text    data     bss     dec     hex filename
 793327     662    7412  801401   c3a79 busybox_old
 793329     641    7372  801342   c3a3e busybox_unstripped