bc: convert all status codes, remove bc_err_msgs[], bc_vm_error(), bc_vm_posixError()

bc: convert all status codes, remove bc_err_msgs[], bc_vm_error(), bc_vm_posixError()

function                                             old     new   delta
bc_posix_error                                         -      65     +65
bc_vm_run                                           1995    2039     +44
bc_err_line                                            7       -      -7
bc_num_ulong                                         103      93     -10
bc_parse_parse                                       495     483     -12
bc_err_fmt                                            12       -     -12
bc_warn_fmt                                           14       -     -14
bc_parse_expr                                       2210    2194     -16
bc_program_reset                                     105      78     -27
bc_vm_process                                        130      94     -36
bc_parse_stmt                                       2313    2277     -36
bc_err_msgs                                           60       -     -60
bc_lex_token                                        1367    1282     -85
bc_vm_error                                          143       -    -143
bc_vm_posixError                                     189       -    -189
------------------------------------------------------------------------------
(add/remove: 1/6 grow/shrink: 1/7 up/down: 109/-647)         Total: -538 bytes
   text	   data	    bss	    dec	    hex	filename
 988258	    485	   7296	 996039	  f32c7	busybox_old
 987717	    485	   7296	 995498	  f30aa	busybox_unstripped

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