Enable DEFINES_MODULE for DoubleConversion

[Kudo]

Summary:

since 32dab7a, DoubleConversion is now added as an implicit dependency for 3rd party module and it breaks swift integration. this pr tries to add the DEFINES_MODULE to DoubleConversion.

Changelog:

[IOS] [FIXED] - Fixed DoubleConversion build error from Swift integration

Test Plan:

i'll need to test this on expo latest and react-native nightly build

# pull latest expo repo and get template tarball
$ git clone --depth 1 https://github.com/expo/expo.git 
$ cd expo
$ yarn install
$ cd templates/expo-template-bare-minimum
$ npx pack --pack-destination ../../

# now create an expo app
$ yarn create expo -t blank@sdk-50 sdk50
$ cd sdk50
$ yarn add react-native@nightly
$ jq '.expo.runtimeVersion = { "policy": "appVersion" }' app.json > app.json.tmp && mv app.json.tmp app.json
$ npx expo prebuild -p ios --template /path/to/expo/expo-template-bare-minimum-50.0.17.tgz
$ cd ios
$ pod install

then it will show the error message:

[!] The following Swift pods cannot yet be integrated as static libraries:

The Swift pod `ExpoModulesCore` depends upon `DoubleConversion`, which does not define modules. To opt into those targets generating module maps (which is necessary to import them from Swift when building as static libraries), you may set `use_modular_headers!` globally in your Podfile, or specify `:modular_headers => true` for particular dependencies.

[cipolleschi]

Thanks for this fix!

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@cipolleschi has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.

[facebook-github-bot]

@cipolleschi merged this pull request in 631b6a1.