The clang that is bundled in Xcode 15 now generates a different "triple" (compilation target) when it sees MACOSX_DEPLOYMENT_TARGET set. Instead of looking at the isysroot, for some reason it overrides that based on MACOSX_DEPLOYMENT_TARGET.

Nix sets MACOSX_DEPLOYMENT_TARGET to 11 for some backwards compatibility reason.

As a result, we started seeing build failures for the glog Pod in Nix after upgrading to Xcode 15.

This diff solves the issue by overriding MACOSX_DEPLOYMENT_TARGET to the empty string.

1. To reproduce the error, you first need to clear your pods cache: pod cache clean --all && rm -rf native/ios/Pods
2. Then try running a yarn cleaninstall (or manually running yarn postinstall in the root)

Before this diff it failed with Xcode 15 + Nix, but now it succeeds.