Add a flag for each experimental feature to indicate its presence.
That way, if we compile with `NAPI_EXPERIMENTAL` turned on, we'll be
able to distinguish between what `NAPI_EXPERIMENTAL` used to mean on an
old version of the headers when compiling against such an old version,
and what it means on a new version of Node.js.

PR-URL: nodejs#50991
Reviewed-By: Michael Dawson <[email protected]>
Reviewed-By: Vladimir Morozov <[email protected]>
Reviewed-By: Chengzhong Wu <[email protected]>
Backport-PR-URL: nodejs#51804
(cherry picked from commit 727dd28)

    * Create macro for checking new string arguments.
    * Create macro for combining env check and inside-gc check.

PR-URL: nodejs#50664
Reviewed-By: Vladimir Morozov <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Chengzhong Wu <[email protected]>
Backport-PR-URL: nodejs#51804
(cherry picked from commit 5e250bd)

We define a new type called `node_api_nogc_env` as the `const` version
of `napi_env` and `node_api_nogc_finalize` as a variant of
`napi_finalize` that accepts a `node_api_nogc_env` as its first
argument.

We then modify those APIs which do not affect GC state as accepting a
`node_api_nogc_env`. APIs accepting finalizer callbacks are modified to
accept `node_api_nogc_finalize` callbacks. Thus, the only way to attach
a `napi_finalize` callback, wherein Node-APIs affecting GC state may be
called is to call `node_api_post_finalizer` from a
`node_api_nogc_finalize` callback.

In keeping with the process of introducing new Node-APIs, this feature
is guarded by `NAPI_EXPERIMENTAL`. Since this feature modifies APIs
already marked as stable, it is additionally guared by
`NODE_API_EXPERIMENTAL_NOGC_ENV`, so as to provide a further buffer to
adoption. Nevertheless, both guards must be removed upon releasing a
new version of Node-API.

PR-URL: nodejs#50060
Reviewed-By: Chengzhong Wu <[email protected]>
Reviewed-By: Vladimir Morozov <[email protected]>
Reviewed-By: Michael Dawson <[email protected]>
Backport-PR-URL: nodejs#51804
(cherry picked from commit 7a216d5)

We define a new type called `node_api_nogc_env` as the `const` version
of `napi_env` and `node_api_nogc_finalize` as a variant of
`napi_finalize` that accepts a `node_api_nogc_env` as its first
argument.

We then modify those APIs which do not affect GC state as accepting a
`node_api_nogc_env`. APIs accepting finalizer callbacks are modified to
accept `node_api_nogc_finalize` callbacks. Thus, the only way to attach
a `napi_finalize` callback, wherein Node-APIs affecting GC state may be
called is to call `node_api_post_finalizer` from a
`node_api_nogc_finalize` callback.

In keeping with the process of introducing new Node-APIs, this feature
is guarded by `NAPI_EXPERIMENTAL`. Since this feature modifies APIs
already marked as stable, it is additionally guared by
`NODE_API_EXPERIMENTAL_NOGC_ENV`, so as to provide a further buffer to
adoption. Nevertheless, both guards must be removed upon releasing a
new version of Node-API.

PR-URL: nodejs#50060
Reviewed-By: Chengzhong Wu <[email protected]>
Reviewed-By: Vladimir Morozov <[email protected]>
Reviewed-By: Michael Dawson <[email protected]>
Backport-PR-URL: nodejs#51804
(cherry picked from commit 7a216d5)

Add a flag for each experimental feature to indicate its presence.
That way, if we compile with `NAPI_EXPERIMENTAL` turned on, we'll be
able to distinguish between what `NAPI_EXPERIMENTAL` used to mean on an
old version of the headers when compiling against such an old version,
and what it means on a new version of Node.js.

PR-URL: #50991
Reviewed-By: Michael Dawson <[email protected]>
Reviewed-By: Vladimir Morozov <[email protected]>
Reviewed-By: Chengzhong Wu <[email protected]>
Backport-PR-URL: #51804
(cherry picked from commit 727dd28)

    * Create macro for checking new string arguments.
    * Create macro for combining env check and inside-gc check.

PR-URL: #50664
Reviewed-By: Vladimir Morozov <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Chengzhong Wu <[email protected]>
Backport-PR-URL: #51804
(cherry picked from commit 5e250bd)

We define a new type called `node_api_nogc_env` as the `const` version
of `napi_env` and `node_api_nogc_finalize` as a variant of
`napi_finalize` that accepts a `node_api_nogc_env` as its first
argument.

We then modify those APIs which do not affect GC state as accepting a
`node_api_nogc_env`. APIs accepting finalizer callbacks are modified to
accept `node_api_nogc_finalize` callbacks. Thus, the only way to attach
a `napi_finalize` callback, wherein Node-APIs affecting GC state may be
called is to call `node_api_post_finalizer` from a
`node_api_nogc_finalize` callback.

In keeping with the process of introducing new Node-APIs, this feature
is guarded by `NAPI_EXPERIMENTAL`. Since this feature modifies APIs
already marked as stable, it is additionally guared by
`NODE_API_EXPERIMENTAL_NOGC_ENV`, so as to provide a further buffer to
adoption. Nevertheless, both guards must be removed upon releasing a
new version of Node-API.

PR-URL: #50060
Reviewed-By: Chengzhong Wu <[email protected]>
Reviewed-By: Vladimir Morozov <[email protected]>
Reviewed-By: Michael Dawson <[email protected]>
Backport-PR-URL: #51804
(cherry picked from commit 7a216d5)