It's not used and contradicts the idea of dynamic loading.

The auto/module script is extended to understand ngx_module_link=DYNAMIC.
When set, it links the module as a shared object rather than statically
into nginx binary.  The module can later be loaded using the "load_module"
directive.

New auto/module parameter ngx_module_order allows to define module loading
order in complex cases.  By default the order is set based on ngx_module_type.

3rd party modules can be compiled dynamically using the --add-dynamic-module
configure option, which will preset ngx_module_link to "DYNAMIC" before
calling the module config script.

Win32 support is rudimentary, and only works when using MinGW gcc (which
is able to handle exports/imports automatically).

In collaboration with Ruslan Ermilov.

This script simplifies configuration of additional modules,
including 3rd party ones.  The script is extensible, and
will be used to introduce dynamic linking of modules in upcoming
changes.

3rd party module config scripts are called with ngx_module_link
preset to "ADDON" - this allows config scripts to call auto/module
without ngx_module_link explicitly defined, as well as testing if
new interface is in place if compatibility with older nginx versions
is desired.

In collaboration with Ruslan Ermilov.

Additionally, HTTP_HEADERS_FILTER_MODULE now added to HTTP_FILTER_MODULES.
This avoids explict use of modules at the later stages, now only module
lists are used.  This will be needed in later patches.

Splits a request into subrequests, each providing a specific range of response.
The variable "$slice_range" must be used to set subrequest range and proper
cache key.  The directive "slice" sets slice size.

The following example splits requests into 1-megabyte cacheable subrequests.

server {
    listen 8000;

    location / {
        slice 1m;

        proxy_cache cache;
        proxy_cache_key $uri$is_args$args$slice_range;
        proxy_set_header Range $slice_range;
        proxy_cache_valid 200 206 1h;
        proxy_pass http://127.0.0.1:9000;
    }
}

The SPDY support is removed, as it's incompatible with the new module.

stream {
    limit_conn_zone $binary_remote_addr zone=perip:1m;
    limit_conn_log_level error;

    server {
        ...
        limit_conn perip 1;
    }
}