automatically update the LLVM submodule

src/bootstrap/dist.rs

@@ -895,6 +895,8 @@ impl Step for Src {
 
     /// Creates the `rust-src` installer component
     fn run(self, builder: &Builder<'_>) -> GeneratedTarball {
+        builder.update_submodule(&Path::new("src/llvm-project"));
+
         let tarball = Tarball::new_targetless(builder, "rust-src");
 
         // A lot of tools expect the rust-src component to be entirely in this directory, so if you

src/bootstrap/llvm.rs

@@ -1087,6 +1087,8 @@ impl Step for CrtBeginEnd {
 
     /// Build crtbegin.o/crtend.o for musl target.
     fn run(self, builder: &Builder<'_>) -> Self::Output {
+        builder.update_submodule(&Path::new("src/llvm-project"));
+
         let out_dir = builder.native_dir(self.target).join("crt");
 
         if builder.config.dry_run() {
@@ -1153,6 +1155,8 @@ impl Step for Libunwind {
 
     /// Build linunwind.a
     fn run(self, builder: &Builder<'_>) -> Self::Output {
+        builder.update_submodule(&Path::new("src/llvm-project"));
+
         if builder.config.dry_run() {
             return PathBuf::new();
         }