add new config option: include

Signed-off-by: onur-ozkan <work@onurozkan.dev>

src/bootstrap/src/core/config/config.rs

@@ -701,6 +701,7 @@ pub(crate) struct TomlConfig {
     target: Option<HashMap<String, TomlTarget>>,
     dist: Option<Dist>,
     profile: Option<String>,
+    include: Option<Vec<PathBuf>>,
 }
 
 /// This enum is used for deserializing change IDs from TOML, allowing both numeric values and the string `"ignore"`.
@@ -753,7 +754,7 @@ trait Merge {
 impl Merge for TomlConfig {
     fn merge(
         &mut self,
-        TomlConfig { build, install, llvm, gcc, rust, dist, target, profile, change_id }: Self,
+        TomlConfig { build, install, llvm, gcc, rust, dist, target, profile, change_id, include }: Self,
         replace: ReplaceOpt,
     ) {
         fn do_merge<T: Merge>(x: &mut Option<T>, y: Option<T>, replace: ReplaceOpt) {
@@ -766,6 +767,17 @@ impl Merge for TomlConfig {
             }
         }
 
+        for include_path in include.clone().unwrap_or_default() {
+            let included_toml = Config::get_toml(&include_path).unwrap_or_else(|e| {
+                eprintln!(
+                    "ERROR: Failed to parse default config profile at '{}': {e}",
+                    include_path.display()
+                );
+                exit!(2);
+            });
+            self.merge(included_toml, ReplaceOpt::Override);
+        }
+
         self.change_id.inner.merge(change_id.inner, replace);
         self.profile.merge(profile, replace);
 
@@ -1600,6 +1612,17 @@ impl Config {
             toml.merge(included_toml, ReplaceOpt::IgnoreDuplicate);
         }
 
+        for include_path in toml.include.clone().unwrap_or_default() {
+            let included_toml = get_toml(&include_path).unwrap_or_else(|e| {
+                eprintln!(
+                    "ERROR: Failed to parse default config profile at '{}': {e}",
+                    include_path.display()
+                );
+                exit!(2);
+            });
+            toml.merge(included_toml, ReplaceOpt::Override);
+        }
+
         let mut override_toml = TomlConfig::default();
         for option in flags.set.iter() {
             fn get_table(option: &str) -> Result<TomlConfig, toml::de::Error> {

src/bootstrap/src/utils/change_tracker.rs

@@ -396,4 +396,9 @@ pub const CONFIG_CHANGE_HISTORY: &[ChangeInfo] = &[
         severity: ChangeSeverity::Info,
         summary: "Added a new option `build.compiletest-use-stage0-libtest` to force `compiletest` to use the stage 0 libtest.",
     },
+    ChangeInfo {
+        change_id: 138934,
+        severity: ChangeSeverity::Info,
+        summary: "Added new option `include` to create config extensions.",
+    },
 ];