add cache command field to bootstrap toml

Author: Shourya742

src/bootstrap/src/core/config/toml/mod.rs

@@ -49,14 +49,27 @@ pub(crate) struct TomlConfig {
     pub(super) dist: Option<Dist>,
     pub(super) profile: Option<String>,
     pub(super) include: Option<Vec<PathBuf>>,
+    pub(super) cache_cmd: Option<bool>,
 }
 
 impl Merge for TomlConfig {
     fn merge(
         &mut self,
         parent_config_path: Option<PathBuf>,
         included_extensions: &mut HashSet<PathBuf>,
-        TomlConfig { build, install, llvm, gcc, rust, dist, target, profile, change_id, include }: Self,
+        TomlConfig {
+            build,
+            install,
+            llvm,
+            gcc,
+            rust,
+            dist,
+            target,
+            profile,
+            change_id,
+            include,
+            cache_cmd,
+        }: Self,
         replace: ReplaceOpt,
     ) {
         fn do_merge<T: Merge>(x: &mut Option<T>, y: Option<T>, replace: ReplaceOpt) {
@@ -71,6 +84,7 @@ impl Merge for TomlConfig {
 
         self.change_id.inner.merge(None, &mut Default::default(), change_id.inner, replace);
         self.profile.merge(None, &mut Default::default(), profile, replace);
+        self.cache_cmd.merge(None, &mut Default::default(), cache_cmd, replace);
 
         do_merge(&mut self.build, build, replace);
         do_merge(&mut self.install, install, replace);