Pillow fails to build on Linux

🐛 Bug

Same error appears when building the compiler_gym wheel or compiling from source. Clang misses a compiler flag: -fno-semantic-interposition

To Reproduce

Steps to reproduce the behavior:

1. On Linux, pip install compiler_gym
2. Or build from source gives the same error

  clang: error: unknown argument: '-fno-semantic-interposition'
  error: command '/usr/bin/clang' failed with exit code 1
  ----------------------------------------
  ERROR: Failed building wheel for Pillow

The error with -fno-semantic-interposition shows up a lot, omitted here.

Environment

• CompilerGym: current development
• How you installed CompilerGym (conda, pip, source): pip and source in a conda env.
• OS: Linux 18.04.5 LTS
• Python version: 3.9
• Build command you used (if compiling from source): as in documentation
• GCC/clang version (if compiling from source): as in documentation
• Bazel version (if compiling from source): as in documentation
• Versions of any other relevant libraries:

You may use the PyTorch environment collection script to generate most of this information. You can get the script and run it with:

wget https://raw.githubusercontent.com/pytorch/pytorch/master/torch/utils/collect_env.py
# For security purposes, please check the contents of collect_env.py before running it.
python collect_env.py

Additional context

Installing pip install Pillow works ok.

[JD-ETH]

Was able to install once clang+±9 was installed. Will update the Readme to include this. Thanks!

[ChrisCummins]

Great!