fix: build error on `docs.rs`

src/core_ffi/rust_ffi/build.rs

@@ -7,25 +7,29 @@
 
 use cxx_build::CFG;
 
+// TODO: assert version info
+
 fn main() {
-    cmake::Config::new("klotski")
-        .define("CARGO_BUILD:BOOL", "ON")
-        .define("KLSK_ENABLE_TESTING:BOOL", "OFF")
-        .define("KLSK_ENABLE_BENCHMARK:BOOL", "OFF")
-        .define("KLSK_C_FFI:BOOL", "OFF")
-        .define("KLSK_PYTHON_FFI:BOOL", "OFF")
-        .build();
-    println!("cargo:rustc-link-lib=static=klotski_core");
+    if std::env::var("DOCS_RS").is_err() {
+        cmake::Config::new("klotski")
+            .define("CARGO_BUILD:BOOL", "ON")
+            .define("KLSK_ENABLE_TESTING:BOOL", "OFF")
+            .define("KLSK_ENABLE_BENCHMARK:BOOL", "OFF")
+            .define("KLSK_C_FFI:BOOL", "OFF")
+            .define("KLSK_PYTHON_FFI:BOOL", "OFF")
+            .build();
+        println!("cargo:rustc-link-lib=static=klotski_core");
 
-    CFG.include_prefix = "rust_ffi";
-    cxx_build::bridge("src/bridge.rs")
-        .file("adapter/short_code.cc")
-        .file("adapter/common_code.cc")
-        .include("klotski/src/core")
-        .flag("-std=c++23")
-        .flag("-fno-rtti")
-        .flag("-fno-exceptions")
-        .compile("klotski");
+        CFG.include_prefix = "rust_ffi";
+        cxx_build::bridge("src/bridge.rs")
+            .file("adapter/short_code.cc")
+            .file("adapter/common_code.cc")
+            .include("klotski/src/core")
+            .flag("-std=c++23")
+            .flag("-fno-rtti")
+            .flag("-fno-exceptions")
+            .compile("klotski");
+    }
 
     println!("cargo:rerun-if-changed=src/bridge.rs");
     println!("cargo:rerun-if-changed=adapter/short_code.cc");