[DRE-maint] Bug#870043: ruby-psych FTBFS: It seems your ruby installation is missing psych (for YAML output).

[Adrian Bunk]

Source: ruby-psych
Version: 2.2.4-2
Severity: serious

https://buildd.debian.org/status/package.php?p=ruby-psych&suite=sid

...
dh_auto_clean
	dh_ruby --clean
   dh_ruby --clean
jruby -S rake clean
/usr/share/jruby/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:55:in `require':
It seems your ruby installation is missing psych (for YAML output).
To eliminate this warning, please install libyaml and reinstall your ruby.
rake aborted!
LoadError: no such file to load -- psych
/<<PKGBUILDDIR>>/Rakefile:1:in `(root)'
/<<PKGBUILDDIR>>/Rakefile:13:in `block in (root)'
(See full trace by running task with --trace)
debian/rules:24: recipe for target 'override_dh_auto_clean' failed
make[1]: *** [override_dh_auto_clean] Error 1