Auto merge of #123144 - dpaoliello:arm64eclib, r=GuillaumeGomez,ChrisDenton,wesleywiser

Add support for Arm64EC to the Standard Library

Adds the final pieces so that the standard library can be built for arm64ec-pc-windows-msvc (initially added in #119199)

* Bumps `windows-sys` to 0.56.0, which adds support for Arm64EC.
* Correctly set the `isEC` parameter for LLVM's `writeArchive` function.
* Add `#![feature(asm_experimental_arch)]` to library crates where Arm64EC inline assembly is used, as it is currently unstable.

compiler/rustc_codegen_llvm/src/back/archive.rs

@@ -415,6 +415,7 @@ impl<'a> LlvmArchiveBuilder<'a> {
                 members.as_ptr() as *const &_,
                 true,
                 kind,
+                self.sess.target.arch == "arm64ec",
             );
             let ret = if r.into_result().is_err() {
                 let err = llvm::LLVMRustGetLastError();

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -2303,6 +2303,7 @@ extern "C" {
         Members: *const &RustArchiveMember<'_>,
         WriteSymbtab: bool,
         Kind: ArchiveKind,
+        isEC: bool,
     ) -> LLVMRustResult;
     pub fn LLVMRustArchiveMemberNew<'a>(
         Filename: *const c_char,