Add a way to set the jobs limit

src/main.rs

@@ -154,6 +154,9 @@ pub struct Cook {
     /// projects that rely on a custom build system (i.e. not `cargo`).
     #[clap(long)]
     no_build: bool,
+    /// Number of rust workers
+    #[clap(long)]
+    jobs: Option<u16>,
 }
 
 fn _main() -> Result<(), anyhow::Error> {
@@ -195,6 +198,7 @@ fn _main() -> Result<(), anyhow::Error> {
             zigbuild,
             bins,
             no_build,
+            jobs,
         }) => {
             if std::io::stdout().is_terminal() {
                 eprintln!("WARNING stdout appears to be a terminal.");
@@ -295,6 +299,7 @@ fn _main() -> Result<(), anyhow::Error> {
                     verbose,
                     bins,
                     no_build,
+                    jobs,
                 })
                 .context("Failed to cook recipe.")?;
         }

src/recipe.rs

@@ -47,6 +47,7 @@ pub struct CookArgs {
     pub bin: Option<Vec<String>>,
     pub bins: bool,
     pub no_build: bool,
+    pub jobs: Option<u16>,
 }
 
 impl Recipe {
@@ -117,6 +118,7 @@ fn build_dependencies(args: &CookArgs) {
         no_std: _no_std,
         bins,
         no_build: _no_build,
+        jobs,
     } = args;
     let cargo_path = std::env::var("CARGO").expect("The `CARGO` environment variable was not set. This is unexpected: it should always be provided by `cargo` when invoking a custom sub-command, allowing `cargo-chef` to correctly detect which toolchain should be used. Please file a bug.");
     let mut command = Command::new(cargo_path);
@@ -202,6 +204,10 @@ fn build_dependencies(args: &CookArgs) {
         command_with_args.arg("--bins");
     }
 
+    if let Some(count) = jobs {
+        command_with_args.arg("--jobs").arg(count.to_string());
+    }
+
     execute_command(command_with_args);
 }