Auto merge of #90527 - 12101111:libc_a, r=petrochenkov

Provide standalone libc.a in self-contained for musl and wasi

This is a prerequisites of rust-lang/libc#2272, which in turn fix:

- rust-lang/wg-cargo-std-aware#66
- #89626

Author: bors

src/bootstrap/compile.rs

@@ -197,7 +197,7 @@ fn copy_self_contained_objects(
     t!(fs::create_dir_all(&libdir_self_contained));
     let mut target_deps = vec![];
 
-    // Copies the CRT objects.
+    // Copies the libc and CRT objects.
     //
     // rustc historically provides a more self-contained installation for musl targets
     // not requiring the presence of a native musl toolchain. For example, it can fall back
@@ -208,7 +208,7 @@ fn copy_self_contained_objects(
         let srcdir = builder.musl_libdir(target).unwrap_or_else(|| {
             panic!("Target {:?} does not have a \"musl-libdir\" key", target.triple)
         });
-        for &obj in &["crt1.o", "Scrt1.o", "rcrt1.o", "crti.o", "crtn.o"] {
+        for &obj in &["libc.a", "crt1.o", "Scrt1.o", "rcrt1.o", "crti.o", "crtn.o"] {
             copy_and_stamp(
                 builder,
                 &libdir_self_contained,
@@ -235,7 +235,7 @@ fn copy_self_contained_objects(
                 panic!("Target {:?} does not have a \"wasi-root\" key", target.triple)
             })
             .join("lib/wasm32-wasi");
-        for &obj in &["crt1-command.o", "crt1-reactor.o"] {
+        for &obj in &["libc.a", "crt1-command.o", "crt1-reactor.o"] {
             copy_and_stamp(
                 builder,
                 &libdir_self_contained,