Use -Zno-embed-metadata for the codegen backend and sysroot

This saves about 10MB on the dist size and about 240MB on the build dir
size.

Author: bjorn3

build_system/build_backend.rs

@@ -43,6 +43,8 @@ pub(crate) fn build_backend(
 
     cmd.arg("--release");
 
+    cmd.arg("-Zno-embed-metadata");
+
     eprintln!("[BUILD] rustc_codegen_cranelift");
     crate::utils::spawn_and_wait(cmd);
 

build_system/build_sysroot.rs

@@ -242,6 +242,7 @@ fn build_clif_sysroot_for_triple(
     build_cmd.arg("--release");
     build_cmd.arg("--features").arg("backtrace panic-unwind");
     build_cmd.arg(format!("-Zroot-dir={}", STDLIB_SRC.to_path(dirs).display()));
+    build_cmd.arg("-Zno-embed-metadata");
     build_cmd.env("CARGO_PROFILE_RELEASE_DEBUG", "true");
     build_cmd.env("__CARGO_DEFAULT_LIB_METADATA", "cg_clif");
     if compiler.triple.contains("apple") {
@@ -256,7 +257,7 @@ fn build_clif_sysroot_for_triple(
     for entry in fs::read_dir(build_dir.join("deps")).unwrap() {
         let entry = entry.unwrap();
         if let Some(ext) = entry.path().extension() {
-            if ext == "rmeta" || ext == "d" || ext == "dSYM" || ext == "clif" {
+            if ext == "d" || ext == "dSYM" || ext == "clif" {
                 continue;
             }
         } else {