Minimal data length we expect for further calls was calculated incorrectly
if parsing stopped right after parsing chunk size.  This might in theory
affect clients and/or backends using LF instead of CRLF.

Patch by Dmitry Popov.

On Linux x32 inclusion of sys/sysctl.h produces an error.  As sysctl() is
only used by rtsig event method code, which is legacy and not compiled
in by default on modern linuxes, the sys/sysctl.h file now only included
if rtsig support is enabled.

Based on patch by Serguei I. Ivantsov.

When several "error_log" directives are specified in the same configuration
block, logs are written to all files with a matching log level.

All logs are stored in the singly-linked list that is sorted by log level in
the descending order.

Specific debug levels (NGX_LOG_DEBUG_HTTP,EVENT, etc.) are not supported
if several "error_log" directives are specified.  In this case all logs
will use debug level that has largest absolute value.

The cycle->new_log->log_level should only be initialized by ngx_init_cycle()
if no error logs were found in the configuration.  This move allows to get rid
of extra initialization in ngx_error_log().

Avoid stripping the status text when proxying for compatibility with http.

It was broken by X-Forwarded-For related changes in f7fe817c92a2 (1.3.14)
as hh->offset is no longer 0 for Cookie.