Updated description for XCFramework and AppleSilicon support

README.md

@@ -1,4 +1,55 @@
 # WebRTC binary for SwiftPM (unfinished)
 This project holds binaries of WebRTC framework (iOS & macOS) as releases.
 
-In the future it will hold XCFramework of WebRTC for use with SwiftPM.
+Since release M88 we publish WebRTC framework as XCFramework compiled for:
+* iOS
+* iOS Simulator
+* macOS (Intel)
+* macOS (AppleSilicon)
+
+Currently usage of macOS universal binary (FAT) was not yet tested.
+
+## Building XCFramework
+
+### Download webrtc
+````sh
+git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git
+export PATH=$PATH:/path/to/depot_tools
+
+fetch --nohooks webrtc_ios
+
+git branch -r
+git checkout branch-heads/BRANCH
+
+gclient sync
+````
+
+### Generate iOS and macOS targets
+````sh
+gn gen ../out/mac_x64 --args='target_os="mac" target_cpu="x64" is_component_build=false is_debug=false rtc_libvpx_build_vp9=false enable_stripping=true rtc_enable_protobuf=false'
+
+gn gen ../out/mac_arm64 --args='target_os="mac" target_cpu="arm64" is_component_build=false is_debug=false rtc_libvpx_build_vp9=false enable_stripping=true rtc_enable_protobuf=false'
+
+gn gen ../out/ios_arm64 --args='target_os="ios" target_cpu="arm64" is_component_build=false use_xcode_clang=true is_debug=false  ios_deployment_target="10.0" rtc_libvpx_build_vp9=false use_goma=false ios_enable_code_signing=false enable_stripping=true rtc_enable_protobuf=false enable_ios_bitcode=false treat_warnings_as_errors=false'
+
+gn gen ../out/ios_x64 --args='target_os="ios" target_cpu="x64" is_component_build=false use_xcode_clang=true is_debug=true ios_deployment_target="10.0" rtc_libvpx_build_vp9=false use_goma=false ios_enable_code_signing=false enable_stripping=true rtc_enable_protobuf=false enable_ios_bitcode=false treat_warnings_as_errors=false'
+````
+
+### Generating macOS universal (FAT) binary
+````sh
+mkdir out/mac_universal
+
+cp -R out/mac_x64/WebRTC.framework out/mac_universal/WebRTC.framework
+
+lipo -create -output out/mac_universal/WebRTC.framework/Versions/A/WebRTC out/mac_x64/WebRTC.framework/WebRTC out/mac_arm64/WebRTC.framework/WebRTC
+````
+
+### Generating XCFramework
+````sh
+xcodebuild -create-xcframework \
+	-framework out/ios_arm64/WebRTC.framework \
+	-framework out/ios_x64/WebRTC.framework \
+	-framework out/mac_universal/WebRTC.framework \
+	-output out/WebRTC.xcframework
+````
+