busybox

bc: move ^C check fro power calculation to multiplication

function                                             old     new   delta
bc_num_k                                             971     990     +19
bc_num_p                                             507     478     -29
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(add/remove: 0/0 grow/shrink: 1/1 up/down: 19/-29)            Total: -10 bytes

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