[lld-macho] Silence XAR deprecation warning

[keith]

Summary

If you're building this on macOS 12.x+ this produces a deprecation
warning. I'm not sure what this means for the bitcode format going
forward, but it seems safe to silence for now.

Do we need to worry about GCC for this?

[int3]

Thanks!

[int3]

Do we need to worry about GCC for this?

I guess if someone is using GCC and are likewise affected, they can submit another diff accordingly...

lld/MachO/SyntheticSections.cpp

if (ec)                                                                    \
             #exp);                                                             \
   } while (0);
 
 void BitcodeBundleSection::finalize() {
 #ifdef LLVM_HAVE_LIBXAR
   using namespace llvm::sys::fs;
   CHECK_EC(createTemporaryFile("bitcode-bundle", "xar", xarPath));
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
   xar_t xar(xar_open(xarPath.data(), O_RDWR));
+#pragma clang diagnostic pop
   if (!xar)
     fatal("failed to open XAR temporary file at " + xarPath);
   CHECK_EC(xar_opt_set(xar, XAR_OPT_COMPRESSION, XAR_OPT_VAL_NONE));
   // FIXME: add more data to XAR
   CHECK_EC(xar_close(xar));
 
   file_size(xarPath, xarSize);
 #endif // defined(LLVM_HAVE_LIBXAR)