utf8 encode util code fix

cf. commit SHA-1: 89bd7a6c37fd36d8c19a77231b66efa30f31e6cb:

local var c3 is not declared hence incorrectly treated as a *global* var. This edit was originally (in slightly altered form) observed in Yuri Karpenko's branch: (commit 45c89379ab3623bd0e31b22088f0255b6af85d08)