Refusing to link macOS provided/shadowed software: icu4c If you need to have icu4c first in your PATH, run: echo 'export PATH="/usr/local/opt/icu4c/bin:$PATH"' >> /Users/runner/.bash_profile echo 'export PATH="/usr/local/opt/icu4c/sbin:$PATH"' >> /Users/runner/.bash_profile For compilers to find icu4c you may need to set: export LDFLAGS="-L/usr/local/opt/icu4c/lib" export CPPFLAGS="-I/usr/local/opt/icu4c/include" For pkg-config to find icu4c you may need to set: export PKG_CONFIG_PATH="/usr/local/opt/icu4c/lib/pkgconfig"