Ignored -std=c++17 on Mac OS X

[genos]

First off, thank you very much for this tutorial! I've been meaning to pick up both bazel and MLIR, so this is extremely helpful.

One thing I stumbled over in getting set up: apparently, bazel automatically detects XCode and picks a different toolchain, which led to it ignoring the -std=c++17 setting. Exporting BAZEL_USE_CPP_ONLY_TOOLCHAIN=1 in my shell ensured that the setting went through. I thought I'd share to save others the trouble I went through.

Thanks again!

[steeve]

I use this with success

build       --cxxopt='-std=c++17'
build       --host_cxxopt='-std=c++17'

[j2kun]

I tried putting both the env and the cxxopt flags in

5d09716

@genos would you have a chance to test it? I don't have a mac to try it on.

[genos]

Interestingly, putting the environment flag in my .bazelrc (after removing it from my ~/.zshrc) didn't work, but putting the other pieces in did. That is, the following .bazelrc works for me:

build --action_env=BAZEL_CXXOPTS=-std=c++17
build --cxxopt='-std=c++17'
build --host_cxxopt='-std=c++17'
test --test_output=all

[j2kun]

Thanks! Marking as fixed.

[genos]

@j2kun Just remembered I've got another change needed to get things working on 🍎 silicon; I'll open a new issue to cover it. See (or feel free to ignore!) #11.