QUIC: added proper logging of special values. A number of unsigned variables has a special value, usually -1 or some maximum, which produces huge numeric value in logs and makes them hard to read. In order to distinguish such values in log, they are casted to the signed type and printed as literal '-1'.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


have=NGX_SUPPRESS_WARN . auto/have

have=NGX_SMP . auto/have