Without this patch, the autoloading of the major mode `llvm-mir-mode` is
not generated, which breaks its autoloading functionality.
To test this patch, use the following command to generate an autoload
file:
```console
cd llvm/utils/emacs
emacs --quick --batch --load=package --eval='(package-generate-autoloads "llvm-mir-mode" ".")'
```
Diff of generated autoload files is as follows:
```diff
> (autoload 'llvm-mir-mode "llvm-mir-mode" "\
> A major mode for editing LLVM MIR files.
>
> (fn)" t)
```
CC @bogner for review
d2bfc2b52b