feat(build): Adds nix flake

crates/nargo/Cargo.toml

@@ -34,7 +34,9 @@ color-eyre = "0.6.2"
 
 
 # Backends
-aztec_backend = { optional = true, package = "barretenberg_static_lib", git = "https://github.com/noir-lang/aztec_backend", rev = "2cb523d2ab95249157b22e198d9dcd6841c3eed8" }
+# aztec_backend = { optional = true, package = "barretenberg_static_lib", [git = "https://github.com/noir-lang/aztec_backend", rev = "2cb523d2ab95249157b22e198d9dcd6841c3eed8"] }
+# aztec_backend = { optional = true, package = "barretenberg_static_lib",  path = "../../../aztec_backend/barretenberg_static_lib" }
+aztec_backend = { optional = true, package = "barretenberg_static_lib",  git = "https://github.com/noir-lang/aztec_backend", branch = "kh-bb-sys" }
 aztec_wasm_backend = { optional = true, package = "barretenberg_wasm", git = "https://github.com/noir-lang/aztec_backend", rev = "2cb523d2ab95249157b22e198d9dcd6841c3eed8" }
 marlin_arkworks_backend = { optional = true, git = "https://github.com/noir-lang/marlin_arkworks_backend", rev = "144378edad821bfaa52bf2cacca8ecc87514a4fc" }
 

crates/nargo/build.rs

@@ -1,6 +1,5 @@
 use rustc_version::{version, Version};
 use std::path::Path;
-
 /// Expects that the given directory is an existing path
 fn rerun_if_stdlib_changes(directory: &Path) {
     for entry in std::fs::read_dir(directory).unwrap() {
@@ -22,12 +21,19 @@ fn check_rustc_version() {
     );
 }
 
+const GIT_COMMIT: &&str = &"GIT_COMMIT";
+
 fn main() {
     check_rustc_version();
 
-    build_data::set_GIT_COMMIT();
-    build_data::set_GIT_DIRTY();
-    build_data::no_debug_rebuilds();
+    if let Ok(git_commit) = std::env::var(GIT_COMMIT) {
+        println!("Using environment defined $GIT_COMMIT={git_commit}")
+    } else {
+        println!("Collecting Git Data from system...");
+        build_data::set_GIT_COMMIT();
+        build_data::set_GIT_DIRTY();
+        build_data::no_debug_rebuilds();
+    }
 
     let stdlib_src_dir = Path::new("../../noir_stdlib/");
     rerun_if_stdlib_changes(stdlib_src_dir);