==> Creating clean working copy [build]...done
==> Making package: ruby-curb 0.8.5-2 (Tue Jan  5 08:47:53 EST 2016)
==> Retrieving sources...
  -> Found curb-0.8.5.gem
==> Validating source files with md5sums...
    curb-0.8.5.gem ... Passed
resolving dependencies...
looking for conflicting packages...

Packages (2) libyaml-0.1.6-1  ruby-2.3.0-1

Total Download Size:    4.62 MiB
Total Installed Size:  22.37 MiB

:: Proceed with installation? [Y/n] 
:: Retrieving packages ...
downloading libyaml-0.1.6-1-x86_64.pkg.tar.xz...
downloading ruby-2.3.0-1-x86_64.pkg.tar.xz...
checking keyring...
checking package integrity...
loading package files...
checking for file conflicts...
checking available disk space...
installing libyaml...
installing ruby...
The default location of gem installs is $HOME/.gem/ruby
Add the following line to your PATH if you plan to install using gem
$(ruby -rubygems -e "puts Gem.user_dir")/bin
If you want to install to the system wide location, you must either:
edit /etc/gemrc or run gem with the --no-user-install flag.
Optional dependencies for ruby
    ruby-docs: Ruby documentation
    tk: for Ruby/TK
Building native extensions.  This could take a while...
checking dependencies...

Packages (2) libyaml-0.1.6-1  ruby-2.3.0-1

Total Removed Size:  22.37 MiB

:: Do you want to remove these packages? [Y/n] 
removing ruby...
removing libyaml...

==> ERROR: Build failed, check /chroot/x86_64/build/build