Big Sur, XCode 12.5.1, link fails

[rjrjr]

ld: library not found for -lSystem

Workaround is to add this block to ios_app/build-rust-xcode.sh

# From https://github.com/TimNN/cargo-lipo/issues/41#issuecomment-774793892
if [[ -n "${DEVELOPER_SDK_DIR:-}" ]]; then
  # Assume we're in Xcode, which means we're probably cross-compiling.
  # In this case, we need to add an extra library search path for build scripts and proc-macros,
  # which run on the host instead of the target.
  # (macOS Big Sur does not have linkable libraries in /usr/lib/.)
  export LIBRARY_PATH="${DEVELOPER_SDK_DIR}/MacOSX.sdk/usr/lib:${LIBRARY_PATH:-}"
fi

[ivnsch]

Hi there, thanks for submitting these issues! would you like to help maintaining this repo? I'll not have time to review this anytime soon.