Refusing to link macOS provided/shadowed software: libffi
For compilers to find libffi you may need to set:
export LDFLAGS="-L/usr/local/opt/libffi/lib"
export CPPFLAGS="-I/usr/local/opt/libffi/include"
For pkg-config to find libffi you may need to set:
export PKG_CONFIG_PATH="/usr/local/opt/libffi/lib/pkgconfig"