shells: do not need to have math state global

function                                             old     new   delta                           
ash_arith                                              -     143    +143                           
expand_variables                                    2102    2124     +22                           
popstring                                            134     140      +6                           
parse_command                                       1460    1463      +3                           
trapcmd                                              236     238      +2                           
changepath                                           197     196      -1                           
raise_interrupt                                       86      83      -3                           
hush_main                                           1012     991     -21                           
ash_main                                            1388    1364     -24                           
arith_set_local_var                                   73      34     -39                           
dash_arith                                           117       -    -117                           
------------------------------------------------------------------------------                     
(add/remove: 1/1 grow/shrink: 4/5 up/down: 176/-205)          Total: -29 bytes

2 files changed