Build Garage with Nix

src/garage/admin_rpc.rs

@@ -423,11 +423,11 @@ impl AdminRpcHandler {
 		writeln!(
 			&mut ret,
 			"\nGarage version: {}",
-			git_version::git_version!(
+			option_env!("GIT_VERSION").unwrap_or(git_version::git_version!(
 				prefix = "git:",
 				cargo_prefix = "cargo:",
 				fallback = "unknown"
-			)
+			))
 		)
 		.unwrap();