When prototyping behavior is not explicitly specified, xsubpp emits
a message to stderr asking to do so (see ticket #608).

perl_parse() function expects argv/argc-style argument list,
which according to the C standard must be NULL-terminated,
that is: argv[argc] == NULL.

This change fixes a crash (SIGSEGV) that could happen because
of the buffer overrun during perl module initialization.

Signed-off-by: Piotr Sikora <piotr@cloudflare.com>

Casts between pointers and integers produce warnings on size mismatch.  To
silence them, cast to (u)intptr_t should be used.  Prevoiusly, casts to
ngx_(u)int_t were used in some cases, and several ngx_int_t expressions had
no casts.

As of now it's mostly style as ngx_int_t is defined as intptr_t.

While ngx_get_full_name() might have a bit more descriptive arguments,
the ngx_conf_full_name() is generally easier to use when parsing
configuration and limits exposure of cycle->prefix / cycle->conf_prefix
details.

The ngx_get_full_name() function takes more readable arguments list.

As per perlxs, C preprocessor directives should be at the first
non-whitespace of a line to avoid interpreting them as comments.

#if and #endif are moved so that there are no blank lines before them
to retain them as part of the function body.

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

As of 1.3.9, chunked request body may be available with
r->headers_in.content_length_n <= 0.  Additionally, request body
may be in multiple buffers even if r->request_body_in_single_buf
was requested.