Bitcoin Core CMake-based build system

See: hebasto/bitcoin#3

The stuff below has been outdated.

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This work is in progress...

Current branch to test: https://github.com/hebasto/bitcoin/commits/cmake/pr

Done:

• bitcoind executable, could be disabled with -DBUILD_DAEMON=OFF
• bitcoin-cli executable, could be disabled with -DBUILD_CLI=OFF
• libbitcoinconsensus shared library, could be disabled with -DBUILD_BITCOINCONSENSUS_LIB=OFF
• libbitcoinkernel shared library, could be disabled with -DBUILD_BITCOINKERNEL_LIB=OFF
• wallet support (SQLite, not BDB), could be disabled with -DENABLE_WALLET=OFF
• ccache support, could be disabled with -DUSE_CCACHE=OFF
• cross-compiling, including Windows builds with DEBUG=1
• reduce exported symbols support, could be enabled with -DREDUCE_EXPORTS=ON (broken on macOS yet)

Not implemented yet:

• optional package support
• BDB wallet support
• ...

Need to be fixed:

• -DREDUCE_EXPORTS=ON on macOS

A benefit to note -- cross compiling libbitcoinconsensus.dll with DEBUG=1 just works (see bitcoin/bitcoin#19772)

Native compiling has been tested on the following OSes:

• Ubuntu 22.04
• macOS Monterey
• FreeBSD 12.3

rm -rf build && cmake -S . -B build
cmake --build build

• OpenBSD 7.1

rm -rf build && cmake -DCMAKE_MAKE_PROGRAM=gmake -S . -B build
cmake --build build

Cross compiling for Windows on Ubuntu 22.04

make -j$(nproc) -C depends HOST=x86_64-w64-mingw32 NO_QT=1
rm -rf build && cmake -C $PWD/depends/x86_64-w64-mingw32/share/depends.cmake -S . -B build
cmake --build build -j$(nproc)

Cross compiling for macOS on Ubuntu 22.04

make -j$(nproc) -C depends HOST=x86_64-apple-darwin NO_QT=1
rm -rf build && cmake -C $PWD/depends/x86_64-apple-darwin/share/depends.cmake -S . -B build
cmake --build build -j$(nproc)