Merge pull request #85 from RustAudio/mike-fix-ios-ci-2

Fix iOS CI

Author: MichaelHills

examples/ios/build_rust_deps.sh

@@ -4,6 +4,14 @@ set -e
 
 PATH=$PATH:$HOME/.cargo/bin
 
+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
+
 # If you want your build to run faster, add a "--targets x86_64-apple-ios" for just using the ios simulator.
 if [ -n ${IOS_TARGETS} ]; then
     cargo lipo --targets ${IOS_TARGETS}