Use cmake-rn

[kraenhansen]

I wanted to show how I intended the React Native Node-API tooling to be used: cmake-rn taking control of the building of Apple frameworks and construction of the Xcframework.

It builds 🤷 But I haven't tried running it (because I don't know how to 🙈) and I am without a doubt missing context for what I'm suggesting here 😁 Feel free to pick whatever makes sense to the project (if any).

Arguably, you could also move the call to cmake-rn all the way out to the package.json as a package script, like we do in the host when building weak-node-api.

Note: This is currently missing linking with weak-node-api as per https://github.com/callstackincubator/react-native-node-api/tree/main/packages/cmake-rn#linking-against-node-api

# Defines the "weak-node-api" target
include(${WEAK_NODE_API_CONFIG})
target_link_libraries(addon PRIVATE weak-node-api)

☝️ is because callstackincubator/react-native-node-api#192 causing weak-node-api to miss an x86_64 slice.

[shirakaba]

Thanks so much for this. Sorry for the terribly late response. Currently reviewing in branch jb/cmake-rn. It looks great, I just need to make some additions to get it all working. Once I've managed that, I'll catch up with the recent changes in main.

[shirakaba]

Previously, cmake_build would be run for each platform, like this:

# Conditions for this example:
BUILD_IPHONE=true
BUILD_SIMULATOR=true
EMBED_METADATA=true
TARGET_ENGINE=none

# (1) Result of calling `cmake_build ios-sim x86_64 arm64`:
# (1a) Generate intermediate project
cmake \
  --source=./NativeScript \
  --build=dist/intermediates/ios-sim \
  -GXcode \
  -DTARGET_PLATFORM=ios-sim \
  -DTARGET_ENGINE=none \
  -DMETADATA_SIZE=1234 \
  -DBUILD_CLI_BINARY=false

# (1b) Build intermediate project
cmake \
  --build dist/intermediates/ios-sim \
  --config RelWithDebInfo

# (2) Result of calling `cmake_build ios arm64`:
# (2a) Generate intermediate project
cmake \
  --source=./NativeScript \
  --build=dist/intermediates/ios \
  -GXcode \
  -DTARGET_PLATFORM=ios \
  -DTARGET_ENGINE=none \
  -DMETADATA_SIZE=1234 \
  -DBUILD_CLI_BINARY=false

# (2b) Build intermediate project
cmake \
  --build dist/intermediates/ios \
  --config RelWithDebInfo

# etc.

We still need to preserve that behaviour for React Native builds, i.e. TARGET_ENGINE=none, with any value of EMBED_METADATA (EMBED_METADATA may be true or false, depending on whether we want to provide metadata for the whole iOS SDK up-front, or let users generate it at app build time so that it can be specific to the code that their project is linking).

When using cmake-rn with TRIPLETS, I'm not clear how we can:

1. In step a, separately specify the metadata size for each platform in the triplet (as it will indeed differ by platform)
2. In step b, build the intermediate project for each triplet.

How can we solve that?