add optional header and hashlib implementation for optional · YosysHQ/yosys@21d6f96

Process completed with exit code 2.

pkg-config 0.29.2_3 is already installed and up-to-date. To reinstall 0.29.2_3, run: brew reinstall pkg-config

HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK is set: not checking for outdated dependents or dependents with broken linkage!