Add an optional solver feature

components/equihash/Cargo.toml

@@ -9,12 +9,18 @@ license = "MIT OR Apache-2.0"
 edition = "2021"
 rust-version = "1.56.1"
 
+[features]
+default = []
+
+## Builds the C++ tromp solver and Rust FFI layer.
+solver = ["dep:cc"]
+
 [dependencies]
 blake2b_simd = "1"
 byteorder = "1"
 
 [build-dependencies]
-cc = "1"
+cc = { version = "1", optional = true }
 
 [dev-dependencies]
 hex = "0.4"

components/equihash/build.rs

@@ -1,11 +1,13 @@
 //! Build script for the equihash tromp solver in C.
 
 fn main() {
+    #[cfg(feature = "solver")]
     cc::Build::new()
         .include("tromp/")
         .file("tromp/equi_miner.c")
         .compile("equitromp");
 
     // Tell Cargo to only rerun this build script if the tromp C files or headers change.
+    #[cfg(feature = "solver")]
     println!("cargo:rerun-if-changed=tromp");
 }

components/equihash/src/lib.rs

@@ -27,5 +27,7 @@ mod test_vectors;
 
 pub use verify::{is_valid_solution, Error};
 
+#[cfg(feature = "solver")]
 mod blake2b;
+#[cfg(feature = "solver")]
 pub mod tromp;