MRuby::Toolchain.new(:clang) do |conf, _params| toolchain :gcc, default_command: 'clang' [conf.cc, conf.objc, conf.asm].each do |cc| cc.flags << '-Wzero-length-array' unless ENV['CFLAGS'] end conf.cxx.flags << '-Wzero-length-array' unless ENV['CXXFLAGS'] || ENV['CFLAGS'] end