Add a mode to `ir_minimizer_main` to compare to the results of optimi…

Fix a couple of missing LLVM headers.

PiperOrigin-RevId: 646260185

Enable use of a separately-run gRPC server with xls_delay_model_gener…

Internal change

PiperOrigin-RevId: 645021172

Integrate LLVM at llvm/llvm-project@99c43e3ce314

Updates LLVM usage to match
[99c43e3ce314](https://github.com/llvm/llvm-project/commit/99c43e3ce314)

PiperOrigin-RevId: 644739615

Add xls_init_xls

Add C API method to init XLS. This method is not stable and subject to change.

PiperOrigin-RevId: 644596897

Add contrib directory for XLA2XLS flow

PiperOrigin-RevId: 644142215

Update priority select's codegen.

1) Always use the `unique` modifier when using SystemVerilog.
2) Instead of putting the value for selector==0 in the `default` case arm, make an explicit case arm for 0.
3) Make the default case arm propagate X.
4) Use wildcards with one-hot selectors and rely on `unique` to flag an error if the selector is not one-hot.

PiperOrigin-RevId: 643487953

Fix a few more minor issues in documentation.

* Correctly stylize a few notes in DSLX std library docs.
* Fix typo in IR overview.

PiperOrigin-RevId: 643128163

Description how to get release: use standard shell tools.

Don't put the user through the hassle to first have to install
some scripting language when they can use common tools available
in any shell.

Also set 'silent' flag on curl to adhere to the no-news-are-good-news
Unix principle.

PiperOrigin-RevId: 642802671