build: make depend/bitcoin/ an ExternalProject

This isolates the build system, and allows a future commit to
let the bitcoin_core build system use a different toolchain (using
depends) from the py-bitcoinkernel toolchain.

Author: stickies-v

CMakeLists.txt

@@ -5,18 +5,12 @@ project(py-bitcoinkernel
 # Set install prefix to be relative to the build directory
 set(CMAKE_INSTALL_PREFIX "${CMAKE_BINARY_DIR}")
 
+include(ExternalProject)
+
+add_library(bitcoinkernel SHARED IMPORTED)
 if(DEFINED ENV{BITCOINKERNEL_LIB})
     message(STATUS "Using bitcoinkernel library from BITCOINKERNEL_LIB: $ENV{BITCOINKERNEL_LIB}")
-    add_library(bitcoinkernel SHARED IMPORTED)
-    set_target_properties(bitcoinkernel PROPERTIES
-        IMPORTED_LOCATION "$ENV{BITCOINKERNEL_LIB}"
-    )
-    
-    # Install the imported library to _libs
-    install(FILES "$ENV{BITCOINKERNEL_LIB}"
-        DESTINATION "_libs"
-        COMPONENT Kernel
-    )
+    set(BITCOINKERNEL_PATH "$ENV{BITCOINKERNEL_LIB}")
 else()
     message(STATUS "Building bitcoinkernel from source in depend/bitcoin/")
     message(STATUS "Using toolchain for host: ${HOST_TUPLE}")
@@ -25,34 +19,51 @@ else()
         message(FATAL_ERROR "Bitcoin source not found in depend/bitcoin/. Please ensure the submodule is initialized.")
     endif()
 
-    # Configure Bitcoin build options
-    set(BUILD_SHARED_LIBS ON)
-    set(BUILD_KERNEL_LIB ON)
-    set(BUILD_BENCH OFF)
-    set(BUILD_CLI OFF)
-    set(BUILD_DAEMON OFF)
-    set(BUILD_FOR_FUZZING OFF)
-    set(BUILD_FUZZ_BINARY OFF)
-    set(BUILD_GUI OFF)
-    set(BUILD_KERNEL_TEST OFF)
-    set(BUILD_TESTS OFF)
-    set(BUILD_TX OFF)
-    set(BUILD_UTIL OFF)
-    set(BUILD_UTIL_CHAINSTATE OFF)
-    set(BUILD_WALLET_TOOL OFF)
-    set(ENABLE_WALLET OFF)
-    set(WITH_SQLITE OFF)
-
-    add_subdirectory(depend/bitcoin EXCLUDE_FROM_ALL)
-
-    # Make bitcoinkernel part of the default build
-    set_target_properties(bitcoinkernel PROPERTIES
-        EXCLUDE_FROM_ALL FALSE
+    ExternalProject_Add(bitcoin_core
+        SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/depend/bitcoin"
+        CMAKE_ARGS
+            -DCMAKE_INSTALL_PREFIX=<INSTALL_DIR>
+            -DCMAKE_INSTALL_LIBDIR=${CMAKE_INSTALL_LIBDIR}
+            -DCMAKE_OSX_ARCHITECTURES=${CMAKE_OSX_ARCHITECTURES}
+            -DCMAKE_OSX_DEPLOYMENT_TARGET=${CMAKE_OSX_DEPLOYMENT_TARGET}
+            -DBUILD_SHARED_LIBS=ON
+            -DBUILD_KERNEL_LIB=ON
+            -DBUILD_BENCH=OFF
+            -DBUILD_CLI=OFF
+            -DBUILD_DAEMON=OFF
+            -DBUILD_FOR_FUZZING=OFF
+            -DBUILD_FUZZ_BINARY=OFF
+            -DBUILD_GUI=OFF
+            -DBUILD_KERNEL_TEST=OFF
+            -DBUILD_TESTS=OFF
+            -DBUILD_TX=OFF
+            -DBUILD_UTIL=OFF
+            -DBUILD_UTIL_CHAINSTATE=OFF
+            -DBUILD_WALLET_TOOL=OFF
+            -DENABLE_WALLET=OFF
+            -DWITH_SQLITE=OFF
+        BUILD_COMMAND ${CMAKE_COMMAND} --build <BINARY_DIR> --target bitcoinkernel
+        INSTALL_COMMAND
+            ${CMAKE_COMMAND} --install <BINARY_DIR> --strip --component Kernel
     )
 
-    install(TARGETS bitcoinkernel
-        COMPONENT Kernel
-        LIBRARY DESTINATION "_libs"
-        RUNTIME DESTINATION "_libs"
-    )
+    # Create imported target for bitcoinkernel
+    add_dependencies(bitcoinkernel bitcoin_core)
+
+    ExternalProject_Get_Property(bitcoin_core INSTALL_DIR)
+    set(RELATIVE_INSTALL_PATH "${CMAKE_INSTALL_LIBDIR}/libbitcoinkernel${CMAKE_SHARED_LIBRARY_SUFFIX}")
+    if(BITCOIN_TARGET MATCHES ".*mingw.*" OR BITCOIN_TARGET MATCHES ".*windows.*")
+        set(RELATIVE_INSTALL_PATH "bin/libbitcoinkernel.dll")
+    endif()
+    set(BITCOINKERNEL_PATH "${INSTALL_DIR}/${RELATIVE_INSTALL_PATH}")
+
 endif()
+
+set_target_properties(bitcoinkernel PROPERTIES
+    IMPORTED_LOCATION "${BITCOINKERNEL_PATH}"
+)
+
+install(FILES "${BITCOINKERNEL_PATH}"
+    DESTINATION "_libs"
+    COMPONENT Kernel
+)