Monero native library for iOS

The wallet runs monero-project wallet2 (plus monero-cpp as the C++ API) on device. Everything is compiled into a single static archive that the app links.

Artifacts

File	Architecture	Platform
`libs/libkoins_monero_merged.a`	arm64	iOS simulator
`libs/libkoins_monero_device.a`	arm64	iOS device

Both are needed: they are the same CPU architecture but different platforms, so they cannot be merged into one fat archive. project.yml selects the right one per SDK.

Prerequisites

Xcode with the iOS device and simulator SDKs
CMake 3.2x (monero 0.18 is not tested with CMake 4)
GNU make (the builds use the "Unix Makefiles" generator)
Roughly 10 GB of disk and a long coffee break

Sources

monero-project v0.18.5.1
monero-cpp (woodser), which keeps monero-project at external/monero-project

Toolchain customisations

The files under depends/ are the ones modified from upstream, kept here so the archive can be regenerated:

File	Change
`depends/hosts/ios.mk`	new host; `IOS_PLATFORM=SIMULATOR` (default) or `DEVICE` selects the SDK and the target triple (`aarch64-apple-ios[-simulator]`)
`depends/packages/packages.mk`	`ios_packages := boost openssl zeromq expat unbound sodium` (no libiconv)
`depends/packages/boost.mk`	boost for the `ios` toolset: darwin toolset, libtool archiver, c++11, no b2 python
`depends/packages/zeromq.mk`	ios config opts (`--host=aarch64-apple-darwin`), no libsodium, no curve
`depends/packages/unbound.mk`	drops the autoconf dependency
`depends/packages/sodium.mk`	drops the autoconf dependency
`depends/funcs.mk`	create the prefix `lib` directory before extracting dependency archives

One source change is also required, in monero-project:

src/cryptonote_basic/miner.cpp — wrap the IOKit includes and the related code with defined(TARGET_OS_OSX) && TARGET_OS_OSX; IOKit is unavailable on iOS. Two locations, around lines 51 and 986.

Two more steps are needed when targeting a device:

Copy monero's patched boost serialisation headers into the dependency prefix, because monero's build otherwise only finds them for the platform it was installed for:
```
cp external/boost/archive/portable_binary_*.hpp \
   contrib/depends/$HOST/include/boost/archive/
```
randomx's AArch64 JIT references __clear_cache, which libSystem exports on macOS and the simulator but not on iOS. The app supplies it in Koins/Support/ClearCache.c.

Build

Set PLATFORM to SIMULATOR or DEVICE; the only differences are the depends host flag and the output archive name.

MONERO=/path/to/monero-project
PLATFORM=SIMULATOR          # or DEVICE
HOST=aarch64-apple-ios

# 1. Cross-compiled dependencies (boost, openssl, zeromq, expat, unbound, sodium)
cd "$MONERO/contrib/depends"
make HOST=$HOST IOS_PLATFORM=$PLATFORM -j"$(sysctl -n hw.ncpu)"

# 2. monero-project, static wallet library
cd "$MONERO"
mkdir -p build/ios-$PLATFORM && cd build/ios-$PLATFORM
cmake -G "Unix Makefiles" \
  -DCMAKE_TOOLCHAIN_FILE="$MONERO/contrib/depends/$HOST/share/toolchain.cmake" \
  -DCMAKE_BUILD_TYPE=Release \
  -DSTATIC=ON -DBUILD_SHARED_LIBS=OFF \
  -DBUILD_TESTS=OFF -DBUILD_DOCUMENTATION=OFF -DUSE_DEVICE_TREZOR=OFF \
  ../..
make -j"$(sysctl -n hw.ncpu)" wallet        # produces lib/libwallet.a

# 3. monero-cpp
cd /path/to/monero-cpp
mkdir -p build-ios-$PLATFORM && cd build-ios-$PLATFORM
cmake -G "Unix Makefiles" \
  -DCMAKE_TOOLCHAIN_FILE="$MONERO/contrib/depends/$HOST/share/toolchain.cmake" \
  ../..
make -j"$(sysctl -n hw.ncpu)"               # produces libmonero-cpp.a

# 4. Merge into one archive for the app
libtool -static -o libkoins_monero_merged.a \
  libmonero-cpp.a \
  "$MONERO/build/ios-$PLATFORM/lib/libwallet.a" \
  "$MONERO/build/ios-$PLATFORM"/src/*/lib*.a \
  "$MONERO/build/ios-$PLATFORM"/external/*/lib*.a \
  "$MONERO/build/ios-$PLATFORM"/contrib/epee/src/libepee.a \
  "$MONERO/contrib/depends/$HOST"/lib/lib*.a

Copy the result to libs/, using libkoins_monero_merged.a for the simulator and libkoins_monero_device.a for the device.

Notes

Only the simulator archive is needed to run in the simulator; the device archive is needed for a real iPhone, and Xcode requires the matching one at link time.
Building the device slice after a simulator build requires moving the simulator depends prefix aside first, since depends installs into contrib/depends/<host> and both platforms share the host name.
The app also links the OpenSSL that is embedded in this archive, which is how the XRP wallet gets secp256k1 without an extra dependency.