This commit suggests that cast-function-type warnings be ignored
from v8.h. Currently, GCC reports a number of warnings like this:

In file included from ../src/util.h:27,
                 from ../src/aliased_buffer.h:7,
                 from ../src/memory_tracker.h:5,
                 from ../src/base_object.h:27,
                 from ../src/async_wrap.h:27,
                 from ../src/req_wrap.h:6,
                 from ../src/req_wrap-inl.h:6,
                 from ../src/connect_wrap.h:6,
                 from ../src/connect_wrap.cc:1:
../deps/v8/include/v8.h: In instantiation of
‘void v8::PersistentBase<T>::SetWeak(
    P*,
    typename v8::WeakCallbackInfo<P>::Callback, v8::WeakCallbackType)
[with
P = node::BaseObject;
T = v8::Object;
typename v8::WeakCallbackInfo<P>::Callback =
    void (*)(const v8::WeakCallbackInfo<node::BaseObject>&)]’:

../src/base_object-inl.h:123:42:   required from here
../deps/v8/include/v8.h:10374:16: warning:
cast between incompatible function types from
‘v8::WeakCallbackInfo<node::BaseObject>::Callback’
{aka ‘void (*)(const v8::WeakCallbackInfo<node::BaseObject>&)’} to
‘Callback’
{aka ‘void (*)(const v8::WeakCallbackInfo<void>&)’}
[-Wcast-function-type]
                reinterpret_cast<Callback>(callback), type);
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The motivation for doing this that it makes it difficult to spot
other warnings that might be important. Since it is v8 that
performs this cast I was not able to find a way around it.

PR-URL: #31475
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>