As of PCRE 8.33, config.h.generic no longer contains boolean macros.  Two
of them (SUPPORT_PCRE8 and HAVE_MEMMOVE) were added to appropriate makefiles.
This allows PCRE 8.33 to compile and don't change anything for previous
versions.

Previously, an attempt to build pcre.lib on win32 before anything else
failed due to no pcre.h.

Some systems (notably NetBSD and OpenBSD) lack AI_ADDRCONFIG support.

Reported by Piotr Sikora.

This is done by passing AI_ADDRCONFIG to getaddrinfo().

On Linux, setting net.ipv6.conf.all.disable_ipv6 to 1 will now be
respected.

On FreeBSD, AI_ADDRCONFIG filtering is currently implemented by
attempting to create a datagram socket for the corresponding family,
which succeeds even if the system doesn't in fact have any addresses
of that family configured.  That is, if the system with IPv6 support
in the kernel doesn't have IPv6 addresses configured, AI_ADDRCONFIG
will filter out IPv6 only inside a jail without IPv6 addresses or
with IPv6 disabled.

Previously, if configured with --with-cc="clang -g", the autotest.dSYM
directories were left unremoved.

The $NGX_AUTO_CONFIG_H added to perl module Makefile dependencies to
make sure it's always rebuild after a configure.  It is needed as we
expand various variables used for Makefile generation during configure
(in particular, nginx version).

Dependancy tracking introduced in r5169 were not handled absolute path
names properly.  Absolute names might appear in CORE_DEPS if --with-openssl
or --with-pcre configure arguments are used to build OpenSSL/PCRE
libraries.

Additionally, revert part of r5169 to set NGX_INCS from Makefile
variables.  Makefile variables have $ngx_include_opt in them, which
might result in wrong include paths being used.  As a side effect,
this also restores build with --with-http_perl_module and --without-http
at the same time.