feat(build): move to cmake crate for building script in build.rs

`libbitcoinkernel-sys/build.rs` was executing a cmake binary from the environment and doing some manual
flag and path configuration. The presented changes delegate the same job to the cmake crate which also
handles dependencies accross environments.

Author: jaoleal

libbitcoinkernel-sys/Cargo.toml

@@ -51,5 +51,6 @@ exclude = [
 publish = true
 
 [build-dependencies]
+cmake = "0.1"
 cc = "1.2"
 bindgen = "0.72"

libbitcoinkernel-sys/build.rs

@@ -2,82 +2,66 @@ use bindgen::RustEdition;
 use std::env;
 use std::path::Path;
 use std::path::PathBuf;
-use std::process::Command;
 
 fn main() {
     let bitcoin_dir = Path::new("bitcoin");
-    let out_dir = env::var("OUT_DIR").unwrap();
-    let build_dir = Path::new(&out_dir).join("bitcoin");
-    let install_dir = Path::new(&out_dir).join("install");
-
-    println!("{} {}", bitcoin_dir.display(), build_dir.display());
 
     // Iterate through all files in the Bitcoin Core submodule directory
     println!("cargo:rerun-if-changed={}", bitcoin_dir.display());
 
     let build_config = "RelWithDebInfo";
 
-    Command::new("cmake")
-        .arg("-B")
-        .arg(&build_dir)
-        .arg("-S")
-        .arg(bitcoin_dir)
-        .arg(format!("-DCMAKE_BUILD_TYPE={build_config}"))
-        .arg("-DBUILD_KERNEL_LIB=ON")
-        .arg("-DBUILD_TESTS=OFF")
-        .arg("-DBUILD_BENCH=OFF")
-        .arg("-DBUILD_KERNEL_TEST=OFF")
-        .arg("-DBUILD_TX=OFF")
-        .arg("-DBUILD_WALLET_TOOL=OFF")
-        .arg("-DENABLE_WALLET=OFF")
-        .arg("-DENABLE_EXTERNAL_SIGNER=OFF")
-        .arg("-DBUILD_UTIL=OFF")
-        .arg("-DBUILD_BITCOIN_BIN=OFF")
-        .arg("-DBUILD_DAEMON=OFF")
-        .arg("-DBUILD_UTIL_CHAINSTATE=OFF")
-        .arg("-DBUILD_CLI=OFF")
-        .arg("-DBUILD_FUZZ_BINARY=OFF")
-        .arg("-DBUILD_SHARED_LIBS=OFF")
-        .arg("-DCMAKE_INSTALL_LIBDIR=lib")
-        .arg("-DENABLE_IPC=OFF")
-        .arg(format!("-DCMAKE_INSTALL_PREFIX={}", install_dir.display()))
-        .status()
-        .expect("cmake is required to build libbitcoinkernel. Please install cmake and ensure it is in your PATH.");
-
-    let num_jobs = env::var("NUM_JOBS")
-        .ok()
-        .and_then(|v| v.parse::<u32>().ok())
-        .unwrap_or(1); // Default to 1 if not set
+    let target_os = std::env::var("CARGO_CFG_TARGET_OS").unwrap();
 
-    Command::new("cmake")
-        .arg("--build")
-        .arg(&build_dir)
-        .arg("--config")
-        .arg(build_config)
-        .arg(format!("--parallel={num_jobs}"))
-        .status()
-        .expect("Failed to run cmake build");
+    // On Windows/MSVC, CMake normally adds /DWIN32 and /D_WINDOWS via
+    // CMAKE_CXX_FLAGS_INIT, but setting CMAKE_CXX_FLAGS to empty overrides
+    // that. We must restore these definitions so that code guarded by
+    // #if defined(WIN32) (e.g. cleanse.cpp's SecureZeroMemory path) compiles
+    // correctly instead of falling through to GCC-style inline assembly.
+    let (c_flags, cxx_flags) = if target_os == "windows" {
+        ("/DWIN32 /D_WINDOWS", "/DWIN32 /D_WINDOWS")
+    } else {
+        ("", "")
+    };
 
-    Command::new("cmake")
-        .arg("--install")
-        .arg(&build_dir)
-        .arg("--config")
-        .arg(build_config)
-        .status()
-        .expect("Failed to run cmake install");
+    let output_dir = cmake::Config::new("bitcoin")
+        .profile(build_config)
+        .no_default_flags(true)
+        .define("CMAKE_C_FLAGS", c_flags)
+        .define("CMAKE_CXX_FLAGS", cxx_flags)
+        .define("CMAKE_ASM_FLAGS", "")
+        .define("BUILD_KERNEL_LIB", "ON")
+        .define("BUILD_TESTS", "OFF")
+        .define("BUILD_BENCH", "OFF")
+        .define("BUILD_KERNEL_TEST", "OFF")
+        .define("BUILD_TX", "OFF")
+        .define("BUILD_WALLET_TOOL", "OFF")
+        .define("ENABLE_WALLET", "OFF")
+        .define("ENABLE_EXTERNAL_SIGNER", "OFF")
+        .define("BUILD_UTIL", "OFF")
+        .define("BUILD_BITCOIN_BIN", "OFF")
+        .define("BUILD_DAEMON", "OFF")
+        .define("BUILD_UTIL_CHAINSTATE", "OFF")
+        .define("BUILD_CLI", "OFF")
+        .define("BUILD_FUZZ_BINARY", "OFF")
+        .define("BUILD_SHARED_LIBS", "OFF")
+        .define("CMAKE_INSTALL_LIBDIR", "lib")
+        .define("ENABLE_IPC", "OFF")
+        .build();
 
     // Check if the build system used a multi-config generator
-    let lib_dir = if install_dir.join("lib").join(build_config).exists() {
-        install_dir.join("lib").join(build_config)
+    let lib_dir = if output_dir.join("lib").join(build_config).exists() {
+        output_dir.join("lib").join(build_config)
     } else {
-        install_dir.join("lib")
+        output_dir.join("lib")
     };
+
     println!("cargo:rustc-link-search=native={}", lib_dir.display());
 
     println!("cargo:rustc-link-lib=static=bitcoinkernel");
 
     // Header path for bindgen
-    let include_path = install_dir.join("include");
+    let include_path = output_dir.join("include");
     let header = include_path.join("bitcoinkernel.h");
 
     #[allow(deprecated)]
@@ -97,7 +81,6 @@ fn main() {
         .expect("Couldn't write bindings!");
 
     let compiler = cc::Build::new().get_compiler();
-    let target_os = std::env::var("CARGO_CFG_TARGET_OS").unwrap();
 
     if target_os == "windows" {
         println!("cargo:rustc-link-lib=bcrypt");