Rollup merge of #124033 - bjorn3:ar_archive_writer_0_3_0, r=davidtwco

Sync ar_archive_writer to LLVM 18.1.3

From LLVM 15.0.0-rc3. This adds support for COFF archives containing Arm64EC object files and has various fixes for AIX big archive files.

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -2440,4 +2440,8 @@ extern "C" {
         callback: GetSymbolsCallback,
         error_callback: GetSymbolsErrorCallback,
     ) -> *mut c_void;
+
+    pub fn LLVMRustIs64BitSymbolicFile(buf_ptr: *const u8, buf_len: usize) -> bool;
+
+    pub fn LLVMRustIsECObject(buf_ptr: *const u8, buf_len: usize) -> bool;
 }