current directory: /usr/local/lib/ruby/gems/2.5.0/gems/ffi-1.9.23/ext/ffi_c /usr/local/opt/ruby/bin/ruby -r ./siteconf20180305-50317-1bqw1ti.rb extconf.rb checking for ffi.h... *** extconf.rb failed *** Could not create Makefile due to some reason, probably lack of necessary libraries and/or headers. Check the mkmf.log file for more details. You may need configuration options.
Provided configuration options: true--with-opt-dir true--with-opt-include true--without-opt-include=${opt-dir}/include true--with-opt-lib true--without-opt-lib=${opt-dir}/lib true--with-make-prog true--without-make-prog true--srcdir=. true--curdir true--ruby=/usr/local/Cellar/ruby/2.5.0_2/bin/$(RUBY_BASE_NAME) true--with-ffi_c-dir true--without-ffi_c-dir true--with-ffi_c-include true--without-ffi_c-include=${ffi_c-dir}/include true--with-ffi_c-lib true--without-ffi_c-lib=${ffi_c-dir}/lib true--with-libffi-config true--without-libffi-config true--with-pkg-config true--without-pkg-config /usr/local/Cellar/ruby/2.5.0_2/lib/ruby/2.5.0/mkmf.rb:456:in `try_do': The compiler failed to generate an executable file. (RuntimeError) You have to install development tools first. from /usr/local/Cellar/ruby/2.5.0_2/lib/ruby/2.5.0/mkmf.rb:590:in `try_cpp' truefrom /usr/local/Cellar/ruby/2.5.0_2/lib/ruby/2.5.0/mkmf.rb:1097:in `block in have_header' from /usr/local/Cellar/ruby/2.5.0_2/lib/ruby/2.5.0/mkmf.rb:947:in `block in checking_for' truefrom /usr/local/Cellar/ruby/2.5.0_2/lib/ruby/2.5.0/mkmf.rb:350:in `block (2 levels) in postpone' from /usr/local/Cellar/ruby/2.5.0_2/lib/ruby/2.5.0/mkmf.rb:320:in `open' truefrom /usr/local/Cellar/ruby/2.5.0_2/lib/ruby/2.5.0/mkmf.rb:350:in `block in postpone' from /usr/local/Cellar/ruby/2.5.0_2/lib/ruby/2.5.0/mkmf.rb:320:in `open' truefrom /usr/local/Cellar/ruby/2.5.0_2/lib/ruby/2.5.0/mkmf.rb:346:in `postpone' from /usr/local/Cellar/ruby/2.5.0_2/lib/ruby/2.5.0/mkmf.rb:946:in `checking_for' truefrom /usr/local/Cellar/ruby/2.5.0_2/lib/ruby/2.5.0/mkmf.rb:1096:in `have_header' from extconf.rb:16:in `<main>'
To see why this extension failed to compile, please check the mkmf.log which can be found here: