Merge 79fcbf8cba into c5e44a0435

2025-04-29 14:59:39 -04:00 · 2025-04-29 11:55:56 +02:00 · 2025-04-29 11:55:56 +02:00 · 31b32ea472
commit 31b32ea472
parent c5e44a0435 79fcbf8cba
19 changed files with 69 additions and 47 deletions
--- a/.cirrus.yml
+++ b/.cirrus.yml
@ -172,13 +172,13 @@ task:
    FILE_ENV: "./ci/test/00_setup_env_native_fuzz.sh"

 task:
-  name: 'multiprocess, i686, DEBUG'
+  name: 'no multiprocess, i686, DEBUG'
  << : *GLOBAL_TASK_TEMPLATE
  persistent_worker:
    labels:
      type: medium
  env:
-    FILE_ENV: "./ci/test/00_setup_env_i686_multiprocess.sh"
+    FILE_ENV: "./ci/test/00_setup_env_i686_no_multiprocess.sh"

 task:
  name: 'no wallet, libbitcoinkernel'
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@ -77,7 +77,7 @@ jobs:
          git config user.name "CI"
      - run: |
          sudo apt-get update
-          sudo apt-get install clang ccache build-essential cmake ninja-build pkgconf python3-zmq libevent-dev libboost-dev libsqlite3-dev libdb++-dev systemtap-sdt-dev libzmq3-dev qt6-base-dev qt6-tools-dev qt6-l10n-tools libqrencode-dev -y
+          sudo apt-get install clang ccache build-essential cmake ninja-build pkgconf python3-zmq libevent-dev libboost-dev libsqlite3-dev libdb++-dev systemtap-sdt-dev libzmq3-dev qt6-base-dev qt6-tools-dev qt6-l10n-tools libqrencode-dev libcapnp-dev capnproto -y
      - name: Compile and run tests
        run: |
          # Run tests on commits after the last merge commit and before the PR head commit
@ -133,7 +133,7 @@ jobs:
        run: |
          # A workaround for "The `brew link` step did not complete successfully" error.
          brew install --quiet python@3 || brew link --overwrite python@3
-          brew install --quiet coreutils ninja pkgconf gnu-getopt ccache boost libevent zeromq qt@6 qrencode
+          brew install --quiet coreutils ninja pkgconf gnu-getopt ccache boost libevent zeromq qt@6 qrencode capnp

      - name: Set Ccache directory
        run: echo "CCACHE_DIR=${RUNNER_TEMP}/ccache_dir" >> "$GITHUB_ENV"
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@ -152,7 +152,7 @@ endif()

 cmake_dependent_option(WITH_DBUS "Enable DBus support." ON "CMAKE_SYSTEM_NAME STREQUAL \"Linux\" AND BUILD_GUI" OFF)

-option(ENABLE_IPC "Build multiprocess bitcoin-node and bitcoin-gui executables in addition to monolithic bitcoind and bitcoin-qt executables. Requires libmultiprocess library. Experimental." OFF)
+cmake_dependent_option(ENABLE_IPC "Build multiprocess bitcoin-node and bitcoin-gui executables in addition to monolithic bitcoind and bitcoin-qt executables." ON "NOT WIN32" OFF)
 cmake_dependent_option(WITH_EXTERNAL_LIBMULTIPROCESS "Build with external libmultiprocess library instead of with local git subtree when ENABLE_IPC is enabled. This is not normally recommended, but can be useful for developing libmultiprocess itself." OFF "ENABLE_IPC" OFF)
 if(ENABLE_IPC AND WITH_EXTERNAL_LIBMULTIPROCESS)
  find_package(Libmultiprocess REQUIRED COMPONENTS Lib)
--- a/ci/test/00_setup_env_i686_no_multiprocess.sh
+++ b/ci/test/00_setup_env_i686_no_multiprocess.sh
@ -7,11 +7,11 @@
 export LC_ALL=C.UTF-8

 export HOST=i686-pc-linux-gnu
-export CONTAINER_NAME=ci_i686_multiprocess
+export CONTAINER_NAME=ci_i686_no_multiprocess
 export CI_IMAGE_NAME_TAG="mirror.gcr.io/ubuntu:24.04"
 export CI_IMAGE_PLATFORM="linux/amd64"
 export PACKAGES="llvm clang g++-multilib"
-export DEP_OPTS="DEBUG=1 MULTIPROCESS=1"
+export DEP_OPTS="DEBUG=1 NO_IPC=1"
 export GOAL="install"
 export TEST_RUNNER_EXTRA="--v2transport"
 export BITCOIN_CONFIG="\
@ -20,4 +20,3 @@ export BITCOIN_CONFIG="\
 -DCMAKE_CXX_COMPILER='clang++;-m32' \
 -DAPPEND_CPPFLAGS='-DBOOST_MULTI_INDEX_ENABLE_SAFE_MODE' \
 "
-export BITCOIND=bitcoin-node  # Used in functional tests
--- a/ci/test/00_setup_env_mac_native.sh
+++ b/ci/test/00_setup_env_mac_native.sh
@ -11,7 +11,12 @@ export LC_ALL=C.UTF-8
 export PIP_PACKAGES="--break-system-packages zmq"
 export GOAL="install"
 export CMAKE_GENERATOR="Ninja"
-export BITCOIN_CONFIG="-DBUILD_GUI=ON -DWITH_ZMQ=ON -DREDUCE_EXPORTS=ON"
+export BITCOIN_CONFIG="\
+ -DBUILD_GUI=ON \
+ -DWITH_ZMQ=ON \
+ -DREDUCE_EXPORTS=ON \
+"
 export CI_OS_NAME="macos"
 export NO_DEPENDS=1
 export OSX_SDK=""
+export BITCOIND=bitcoin-node # Used in functional tests
--- a/ci/test/00_setup_env_native_asan.sh
+++ b/ci/test/00_setup_env_native_asan.sh
@ -20,11 +20,15 @@ fi

 export CONTAINER_NAME=ci_native_asan
 export APT_LLVM_V="20"
-export PACKAGES="systemtap-sdt-dev clang-${APT_LLVM_V} llvm-${APT_LLVM_V} libclang-rt-${APT_LLVM_V}-dev python3-zmq qt6-base-dev qt6-tools-dev qt6-l10n-tools libevent-dev libboost-dev libdb5.3++-dev libzmq3-dev libqrencode-dev libsqlite3-dev ${BPFCC_PACKAGE}"
+export PACKAGES="systemtap-sdt-dev clang-${APT_LLVM_V} llvm-${APT_LLVM_V} libclang-rt-${APT_LLVM_V}-dev python3-zmq qt6-base-dev qt6-tools-dev qt6-l10n-tools libevent-dev libboost-dev libdb5.3++-dev libzmq3-dev libqrencode-dev libsqlite3-dev ${BPFCC_PACKAGE} libcapnp-dev capnproto"
 export NO_DEPENDS=1
 export GOAL="install"
 export BITCOIN_CONFIG="\
- -DWITH_USDT=ON -DWITH_ZMQ=ON -DWITH_BDB=ON -DWARN_INCOMPATIBLE_BDB=OFF -DBUILD_GUI=ON \
+ -DWITH_USDT=ON \
+ -DWITH_ZMQ=ON \
+ -DWITH_BDB=ON \
+ -DWARN_INCOMPATIBLE_BDB=OFF \
+ -DBUILD_GUI=ON \
 -DSANITIZERS=address,float-divide-by-zero,integer,undefined \
 -DCMAKE_C_COMPILER=clang-${APT_LLVM_V} \
 -DCMAKE_CXX_COMPILER=clang++-${APT_LLVM_V} \
--- a/ci/test/00_setup_env_native_centos.sh
+++ b/ci/test/00_setup_env_native_centos.sh
@ -13,3 +13,4 @@ export PIP_PACKAGES="pyzmq"
 export DEP_OPTS="DEBUG=1"  # Temporarily enable a DEBUG=1 build to check for GCC-bug-117966 regressions. This can be removed once the minimum GCC version is bumped to 12 in the previous releases task, see https://github.com/bitcoin/bitcoin/issues/31436#issuecomment-2530717875
 export GOAL="install"
 export BITCOIN_CONFIG="-DWITH_ZMQ=ON -DBUILD_GUI=ON -DREDUCE_EXPORTS=ON -DCMAKE_BUILD_TYPE=Debug"
+export BITCOIND=bitcoin-node # Used in functional tests
--- a/ci/test/00_setup_env_native_fuzz.sh
+++ b/ci/test/00_setup_env_native_fuzz.sh
@ -9,7 +9,7 @@ export LC_ALL=C.UTF-8
 export CI_IMAGE_NAME_TAG="mirror.gcr.io/ubuntu:24.04"
 export CONTAINER_NAME=ci_native_fuzz
 export APT_LLVM_V="20"
-export PACKAGES="clang-${APT_LLVM_V} llvm-${APT_LLVM_V} libclang-rt-${APT_LLVM_V}-dev libevent-dev libboost-dev libsqlite3-dev"
+export PACKAGES="clang-${APT_LLVM_V} llvm-${APT_LLVM_V} libclang-rt-${APT_LLVM_V}-dev libevent-dev libboost-dev libsqlite3-dev libcapnp-dev capnproto"
 export NO_DEPENDS=1
 export RUN_UNIT_TESTS=false
 export RUN_FUNCTIONAL_TESTS=false
--- a/ci/test/00_setup_env_native_fuzz_with_valgrind.sh
+++ b/ci/test/00_setup_env_native_fuzz_with_valgrind.sh
@ -8,7 +8,7 @@ export LC_ALL=C.UTF-8

 export CI_IMAGE_NAME_TAG="mirror.gcr.io/ubuntu:24.04"
 export CONTAINER_NAME=ci_native_fuzz_valgrind
-export PACKAGES="libevent-dev libboost-dev libsqlite3-dev valgrind"
+export PACKAGES="libevent-dev libboost-dev libsqlite3-dev valgrind libcapnp-dev capnproto"
 export NO_DEPENDS=1
 export RUN_UNIT_TESTS=false
 export RUN_FUNCTIONAL_TESTS=false
--- a/ci/test/00_setup_env_native_tidy.sh
+++ b/ci/test/00_setup_env_native_tidy.sh
@ -10,7 +10,7 @@ export CI_IMAGE_NAME_TAG="mirror.gcr.io/ubuntu:24.04"
 export CONTAINER_NAME=ci_native_tidy
 export TIDY_LLVM_V="20"
 export APT_LLVM_V="${TIDY_LLVM_V}"
-export PACKAGES="clang-${TIDY_LLVM_V} libclang-${TIDY_LLVM_V}-dev llvm-${TIDY_LLVM_V}-dev libomp-${TIDY_LLVM_V}-dev clang-tidy-${TIDY_LLVM_V} jq libevent-dev libboost-dev libzmq3-dev systemtap-sdt-dev qt6-base-dev qt6-tools-dev qt6-l10n-tools libqrencode-dev libsqlite3-dev libdb++-dev"
+export PACKAGES="clang-${TIDY_LLVM_V} libclang-${TIDY_LLVM_V}-dev llvm-${TIDY_LLVM_V}-dev libomp-${TIDY_LLVM_V}-dev clang-tidy-${TIDY_LLVM_V} jq libevent-dev libboost-dev libzmq3-dev systemtap-sdt-dev qt6-base-dev qt6-tools-dev qt6-l10n-tools libqrencode-dev libsqlite3-dev libdb++-dev libcapnp-dev capnproto"
 export NO_DEPENDS=1
 export RUN_UNIT_TESTS=false
 export RUN_FUNCTIONAL_TESTS=false
@ -19,7 +19,12 @@ export RUN_CHECK_DEPS=true
 export RUN_TIDY=true
 export GOAL="install"
 export BITCOIN_CONFIG="\
- -DWITH_ZMQ=ON -DBUILD_GUI=ON -DBUILD_BENCH=ON -DWITH_USDT=ON -DWITH_BDB=ON -DWARN_INCOMPATIBLE_BDB=OFF \
+ -DWITH_ZMQ=ON \
+ -DBUILD_GUI=ON \
+ -DBUILD_BENCH=ON \
+ -DWITH_USDT=ON \
+ -DWITH_BDB=ON \
+ -DWARN_INCOMPATIBLE_BDB=OFF \
 -DCMAKE_C_COMPILER=clang-${TIDY_LLVM_V} \
 -DCMAKE_CXX_COMPILER=clang++-${TIDY_LLVM_V} \
 -DCMAKE_C_FLAGS_RELWITHDEBINFO='-O0 -g0' \
--- a/ci/test/00_setup_env_native_valgrind.sh
+++ b/ci/test/00_setup_env_native_valgrind.sh
@ -8,12 +8,15 @@ export LC_ALL=C.UTF-8

 export CI_IMAGE_NAME_TAG="mirror.gcr.io/ubuntu:24.04"
 export CONTAINER_NAME=ci_native_valgrind
-export PACKAGES="valgrind python3-zmq libevent-dev libboost-dev libdb5.3++-dev libzmq3-dev libsqlite3-dev"
+export PACKAGES="valgrind python3-zmq libevent-dev libboost-dev libdb5.3++-dev libzmq3-dev libsqlite3-dev libcapnp-dev capnproto"
 export USE_VALGRIND=1
 export NO_DEPENDS=1
 export TEST_RUNNER_EXTRA="--exclude feature_init,rpc_bind,feature_bind_extra"  # feature_init excluded for now, see https://github.com/bitcoin/bitcoin/issues/30011 ; bind tests excluded for now, see https://github.com/bitcoin/bitcoin/issues/17765#issuecomment-602068547
 export GOAL="install"
 # TODO enable GUI
 export BITCOIN_CONFIG="\
- -DWITH_ZMQ=ON -DWITH_BDB=ON -DWARN_INCOMPATIBLE_BDB=OFF -DBUILD_GUI=OFF \
+ -DWITH_ZMQ=ON
+ -DWITH_BDB=ON
+ -DWARN_INCOMPATIBLE_BDB=OFF
+ -DBUILD_GUI=OFF \
 "
--- a/cmake/module/Maintenance.cmake
+++ b/cmake/module/Maintenance.cmake
@ -23,7 +23,7 @@ function(add_maintenance_targets)
    return()
  endif()

-  foreach(target IN ITEMS bitcoind bitcoin-qt bitcoin-cli bitcoin-tx bitcoin-util bitcoin-wallet test_bitcoin bench_bitcoin)
+  foreach(target IN ITEMS bitcoind bitcoin-node bitcoin-qt bitcoin-gui bitcoin-cli bitcoin-tx bitcoin-util bitcoin-wallet test_bitcoin bench_bitcoin)
    if(TARGET ${target})
      list(APPEND executables $<TARGET_FILE:${target}>)
    endif()
--- a/depends/Makefile
+++ b/depends/Makefile
@ -40,7 +40,10 @@ NO_BDB ?=
 NO_WALLET ?=
 NO_ZMQ ?=
 NO_USDT ?=
-MULTIPROCESS ?=
+# Default NO_IPC value is 1 on unsupported host platforms:
+# - Windows
+# - OpenBSD: https://github.com/capnproto/capnproto/pull/1907
+NO_IPC ?= $(if $(findstring mingw32,$(HOST))$(findstring openbsd,$(HOST)),1,)
 LTO ?=
 FALLBACK_DOWNLOAD_PATH ?= https://bitcoincore.org/depends-sources

@ -163,7 +166,7 @@ bdb_packages_$(NO_BDB) = $(bdb_packages)
 wallet_packages_$(NO_WALLET) = $(bdb_packages_) $(sqlite_packages)

 zmq_packages_$(NO_ZMQ) = $(zmq_packages)
-multiprocess_packages_$(MULTIPROCESS) = $(multiprocess_packages)
+multiprocess_packages_$(NO_IPC) = $(multiprocess_packages)
 usdt_packages_$(NO_USDT) = $(usdt_$(host_os)_packages)

 packages += $($(host_arch)_$(host_os)_packages) $($(host_os)_packages) $(boost_packages_) $(libevent_packages_) $(qt_packages_) $(wallet_packages_) $(usdt_packages_)
@ -173,7 +176,7 @@ ifneq ($(zmq_packages_),)
 packages += $(zmq_packages)
 endif

-ifeq ($(multiprocess_packages_),)
+ifneq ($(multiprocess_packages_),)
 packages += $(multiprocess_packages)
 native_packages += $(multiprocess_native_packages)
 endif
@ -234,7 +237,7 @@ $(host_prefix)/toolchain.cmake : toolchain.cmake.in $(host_prefix)/.stamp_$(fina
            -e 's|@wallet_packages@|$(wallet_packages_)|' \
            -e 's|@bdb_packages@|$(bdb_packages_)|' \
            -e 's|@usdt_packages@|$(usdt_packages_)|' \
-            -e 's|@multiprocess@|$(MULTIPROCESS)|' \
+            -e 's|@multiprocess_packages@|$(multiprocess_packages_)|' \
            $< > $@
 	touch $@

--- a/depends/README.md
+++ b/depends/README.md
@ -118,7 +118,7 @@ The following can be set when running make: `make FOO=bar`
 - `NO_WALLET`: Don't download/build/cache libs needed to enable the wallet (SQLite)
 - `NO_BDB`: Don't download/build/cache BerkeleyDB
 - `NO_USDT`: Don't download/build/cache packages needed for enabling USDT tracepoints
- `MULTIPROCESS`: Build libmultiprocess (experimental)
+- `NO_IPC`: Don't build Cap’n Proto and libmultiprocess packages, and disable building IPC binaries (bitcoin-node, bitcoin-gui). Default on Windows and OpenBSD.
 - `DEBUG`: Disable some optimizations and enable more runtime checking
 - `HOST_ID_SALT`: Optional salt to use when generating host package ids
 - `BUILD_ID_SALT`: Optional salt to use when generating build package ids
--- a/depends/toolchain.cmake.in
+++ b/depends/toolchain.cmake.in
@ -158,11 +158,12 @@ else()
  set(WITH_USDT ON CACHE BOOL "")
 endif()

-if("@multiprocess@" STREQUAL "1")
+set(multiprocess_packages @multiprocess_packages@)
+if("${multiprocess_packages}" STREQUAL "")
+  set(ENABLE_IPC OFF CACHE BOOL "")
+else()
  set(ENABLE_IPC ON CACHE BOOL "")
  set(MPGEN_EXECUTABLE "${CMAKE_CURRENT_LIST_DIR}/native/bin/mpgen" CACHE FILEPATH "")
  set(CAPNP_EXECUTABLE "${CMAKE_CURRENT_LIST_DIR}/native/bin/capnp" CACHE FILEPATH "")
  set(CAPNPC_CXX_EXECUTABLE "${CMAKE_CURRENT_LIST_DIR}/native/bin/capnpc-c++" CACHE FILEPATH "")
-else()
-  set(ENABLE_IPC OFF CACHE BOOL "")
 endif()
--- a/doc/build-osx.md
+++ b/doc/build-osx.md
@ -48,9 +48,11 @@ See [dependencies.md](dependencies.md) for a complete overview.
 To install, run the following from your terminal:

 ``` bash
-brew install cmake boost pkgconf libevent
+brew install cmake boost pkgconf libevent capnp
 ```

+It's possible to omit `capnp`, see [below](#IPC-dependencies).
+
 ### 4. Clone Bitcoin repository

 `git` should already be installed by default on your system.
@ -127,12 +129,8 @@ For more information on ZMQ, see: [zmq.md](zmq.md)

 ### IPC Dependencies

-Compiling IPC-enabled binaries with `-DENABLE_IPC=ON` requires the following dependency.
-Skip if you do not need IPC functionality.
-
-```bash
-brew install capnp
-```
+The dependency on `capnp` can be avoided by compiling without IPC-enabled binaries
+using `-DENABLE_IPC=OFF`.

 For more information on IPC, see: [multiprocess.md](multiprocess.md).

--- a/doc/build-unix.md
+++ b/doc/build-unix.md
@ -60,6 +60,12 @@ executables, which are based on BerkeleyDB 4.8. Otherwise, you can build Berkele

 To build Bitcoin Core without wallet, see [*Disable-wallet mode*](#disable-wallet-mode)

+Cap'n Proto is required to build IPC-enabled binaries:
+
+    sudo apt-get install libcapnp-dev capnproto
+
+Compile  with `-DENABLE_IPC=OFF` if you do not need this functionality.
+
 ZMQ dependencies (provides ZMQ API):

    sudo apt-get install libzmq3-dev
@ -68,11 +74,6 @@ User-Space, Statically Defined Tracing (USDT) dependencies:

    sudo apt install systemtap-sdt-dev

-IPC-enabled binaries are compiled  with `-DENABLE_IPC=ON` and require the following dependencies.
-Skip if you do not need IPC functionality.
-
-    sudo apt-get install libcapnp-dev capnproto
-
 GUI dependencies:

 Bitcoin Core includes a GUI built with the cross-platform Qt Framework. To compile the GUI, we need to install
@ -115,6 +116,12 @@ are based on Berkeley DB 4.8. Otherwise, you can build Berkeley DB [yourself](#b

 To build Bitcoin Core without wallet, see [*Disable-wallet mode*](#disable-wallet-mode)

+Cap'n Proto is required to build IPC-enabled binaries:
+
+    sudo dnf install capnp
+
+Compile  with `-DENABLE_IPC=OFF` if you do not need this functionality.
+
 ZMQ dependencies (provides ZMQ API):

    sudo dnf install zeromq-devel
@ -123,11 +130,6 @@ User-Space, Statically Defined Tracing (USDT) dependencies:

    sudo dnf install systemtap-sdt-devel

-IPC-enabled binaries are compiled  with `-DENABLE_IPC=ON` and require the following dependency.
-Skip if you do not need IPC functionality.
-
-    sudo dnf install capnproto
-
 GUI dependencies:

 Bitcoin Core includes a GUI built with the cross-platform Qt Framework. To compile the GUI, we need to install
--- a/doc/dependencies.md
+++ b/doc/dependencies.md
@ -36,3 +36,4 @@ Bitcoin Core requires one of the following compilers.
 | [SQLite](../depends/packages/sqlite.mk) (wallet) | [link](https://sqlite.org) | [3.38.5](https://github.com/bitcoin/bitcoin/pull/25378) | [3.7.17](https://github.com/bitcoin/bitcoin/pull/19077) | No |
 | Python (scripts, tests) | [link](https://www.python.org) | N/A | [3.10](https://github.com/bitcoin/bitcoin/pull/30527) | No |
 | [systemtap](../depends/packages/systemtap.mk) ([tracing](tracing.md)) | [link](https://sourceware.org/systemtap/) | [4.8](https://github.com/bitcoin/bitcoin/pull/26945)| N/A | No |
+| [Cap'n Proto](../depends/packages/capnp.mk) | [link](https://capnproto.org) | [0.6.1](https://capnproto.org/install.html) | 0.5.3 | No |
--- a/doc/multiprocess.md
+++ b/doc/multiprocess.md
@ -4,7 +4,7 @@ _This document describes usage of the multiprocess feature. For design informati

 ## Build Option

-On Unix systems, the `-DENABLE_IPC=ON` build option can be passed to build the supplemental `bitcoin-node` and `bitcoin-gui` multiprocess executables.
+The `-DENABLE_IPC=ON` build option, supported and enabled by default on Unix systems, can be passed to build the supplemental `bitcoin-node` and `bitcoin-gui` multiprocess executables.

 ## Debugging

@ -16,11 +16,11 @@ Specifying `-DENABLE_IPC=ON` requires [Cap'n Proto](https://capnproto.org/) to b

 ### Depends installation

-Alternately the [depends system](../depends) can be used to avoid need to install local dependencies. A simple way to get started is to pass the `MULTIPROCESS=1` [dependency option](../depends#dependency-options) to make:
+Alternatively the [depends system](../depends) can be used to avoid needing to install local dependencies:

 ```
 cd <BITCOIN_SOURCE_DIRECTORY>
-make -C depends NO_QT=1 MULTIPROCESS=1
+make -C depends NO_QT=1
 # Set host platform to output of gcc -dumpmachine or clang -dumpmachine or check the depends/ directory for the generated subdirectory name
 HOST_PLATFORM="x86_64-pc-linux-gnu"
 cmake -B build --toolchain=depends/$HOST_PLATFORM/toolchain.cmake
@ -29,7 +29,7 @@ build/bin/bitcoin-node -regtest -printtoconsole -debug=ipc
 BITCOIND=$(pwd)/build/bin/bitcoin-node build/test/functional/test_runner.py
 ```

-The `cmake` build will pick up settings and library locations from the depends directory, so there is no need to pass `-DENABLE_IPC=ON` as a separate flag when using the depends system (it's controlled by the `MULTIPROCESS=1` option).
+The `cmake` build will pick up settings and library locations from the depends directory, so there is no need to pass `-DENABLE_IPC=ON` as a separate flag when using the depends system (it's controlled by the `NO_IPC=1` option).

 ### Cross-compiling