bitcoin/depends/README.md

### Usage

To build dependencies for the current arch+OS:

    make

To build for another arch/OS:

    make HOST=host-platform-triplet

For example:

    make HOST=x86_64-w64-mingw32 -j4

**Bitcoin's configure script by default will ignore the depends output.** In
order for it to pick up libraries, tools, and settings from the depends build,
you must point it at the appropriate `--prefix` directory generated by the
build. In the above example, a prefix dir named x86_64-w64-mingw32 will be
created. To use it for Bitcoin:

    ./configure --prefix=`pwd`/depends/x86_64-w64-mingw32

Common `host-platform-triplets` for cross compilation are:

- `i686-pc-linux-gnu` for Linux 32 bit
- `x86_64-pc-linux-gnu` for x86 Linux
- `x86_64-w64-mingw32` for Win64
- `x86_64-apple-darwin14` for macOS
- `arm-linux-gnueabihf` for Linux ARM 32 bit
- `aarch64-linux-gnu` for Linux ARM 64 bit
- `riscv32-linux-gnu` for Linux RISC-V 32 bit
- `riscv64-linux-gnu` for Linux RISC-V 64 bit
- `aarch64-linux-android` for Android ARM 64 bit

The paths are automatically configured and no other options are needed unless targeting Android.
Before proceeding with an Android build one needs to get the [Android SDK](https://developer.android.com/studio) and use the "SDK Manager" tool to download the NDK and one or more "Platform packages" (these are Android versions and have a corresponding API level).
In order to build `ANDROID_API_LEVEL` (API level corresponding to the Android version targeted, e.g. Android 9.0 Pie is 28 and its "Platform package" needs to be available) and `ANDROID_TOOLCHAIN_BIN` (path to toolchain binaries depending on the platform the build is being performed on) need to be set.
If the build includes Qt, environment variables `ANDROID_SDK` and `ANDROID_NDK` need to be set as well but can otherwise be omitted.
This is an example command for a default build with no disabled dependencies:

    ANDROID_SDK=/home/user/Android/Sdk ANDROID_NDK=/home/user/Android/Sdk/ndk-bundle make HOST=aarch64-linux-android ANDROID_API_LEVEL=28 ANDROID_TOOLCHAIN_BIN=/home/user/Android/Sdk/ndk-bundle/toolchains/llvm/prebuilt/linux-x86_64/bin



### Install the required dependencies: Ubuntu & Debian

#### For macOS cross compilation

    sudo apt-get install curl librsvg2-bin libtiff-tools bsdmainutils cmake imagemagick libcap-dev libz-dev libbz2-dev python3-setuptools

#### For Win32/Win64 cross compilation

- see [build-windows.md](../doc/build-windows.md#cross-compilation-for-ubuntu-and-windows-subsystem-for-linux)

#### For linux (including i386, ARM) cross compilation

Common linux dependencies:

    sudo apt-get install make automake cmake curl g++-multilib libtool binutils-gold bsdmainutils pkg-config python3 patch

For linux ARM cross compilation:

    sudo apt-get install g++-arm-linux-gnueabihf binutils-arm-linux-gnueabihf

For linux AARCH64 cross compilation:

    sudo apt-get install g++-aarch64-linux-gnu binutils-aarch64-linux-gnu

For linux RISC-V 64-bit cross compilation (there are no packages for 32-bit):

    sudo apt-get install g++-riscv64-linux-gnu binutils-riscv64-linux-gnu

RISC-V known issue: gcc-7.3.0 and gcc-7.3.1 result in a broken `test_bitcoin` executable (see https://github.com/bitcoin/bitcoin/pull/13543),
this is apparently fixed in gcc-8.1.0.

### Dependency Options
The following can be set when running make: make FOO=bar

    SOURCES_PATH: downloaded sources will be placed here
    BASE_CACHE: built packages will be placed here
    SDK_PATH: Path where sdk's can be found (used by macOS)
    FALLBACK_DOWNLOAD_PATH: If a source file can't be fetched, try here before giving up
    NO_QT: Don't download/build/cache qt and its dependencies
    NO_ZMQ: Don't download/build/cache packages needed for enabling zeromq
    NO_WALLET: Don't download/build/cache libs needed to enable the wallet
    NO_UPNP: Don't download/build/cache packages needed for enabling upnp
    DEBUG: disable some optimizations and enable more runtime checking
    RAPIDCHECK: build rapidcheck (experimental, requires cmake)
    HOST_ID_SALT: Optional salt to use when generating host package ids
    BUILD_ID_SALT: Optional salt to use when generating build package ids

If some packages are not built, for example `make NO_WALLET=1`, the appropriate
options will be passed to bitcoin's configure. In this case, `--disable-wallet`.

### Additional targets

    download: run 'make download' to fetch all sources without building them
    download-osx: run 'make download-osx' to fetch all sources needed for macOS builds
    download-win: run 'make download-win' to fetch all sources needed for win builds
    download-linux: run 'make download-linux' to fetch all sources needed for linux builds

### Other documentation

- [description.md](description.md): General description of the depends system
- [packages.md](packages.md): Steps for adding packages