File this one as a niche issue, but in case someone else ends up losing a morning to this issue, I figured I’d post it.
I was trying to update my blog to a newer version of Jekyll. However, my attempts at running bundle update kept running into this error:
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
current directory: /usr/local/lib/ruby/gems/2.3.0/gems/ffi-1.9.18/ext/ffi_c
/usr/local/opt/ruby/bin/ruby -r ./siteconf20170421-40871-1dh28zu.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.
...
/usr/local/Cellar/ruby/2.3.1/lib/ruby/2.3.0/mkmf.rb:456:in 'try_do': The
compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
...
Make sure that \`gem install ffi -v '1.9.18'\` succeeds before bundling.Trying to run the suggested gem install ffi -v '1.9.18' failed as well. The actual solution is in the error but isn’t necessarily obvious. They key is this part: You have to install development tools first. I’m on a Mac, so that means XCode. However, just going to the App Store and getting XCode isn’t enough, the key is in step 2 below.
- Install XCode
- Open XCode
bundle update
I should note that after I did all this, I was still getting warnings when I ran Jekyll.
Unresolved specs during Gem::Specification.reset:
rb-inotify (>= 0.9.7, ~> 0.9)These went away after running a gem cleanup.
Lastly, I was getting a bunch of additional warnings like the following:
warning: already initialized constant JSON::VERSIONThese went away after running bundle clean --force and then rerunning bundle update.
This may seem obvious to some of you (especially those more comfortable in the Ruby environment), but I found a ton of people with similar problems (some specific to Jekyll, others to different Ruby gems), so I figured I’d post it.