Use vterm 0.0.5 or newer on Unix like OSes because suppresses SEGV

Author: aycabta

irb.gemspec

@@ -38,6 +38,8 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency "reline", ">= 0.1.5"
   spec.add_development_dependency "bundler"
+  is_unix = RUBY_PLATFORM =~ /(aix|darwin|linux|(net|free|open)bsd|cygwin|solaris|irix|hpux)/i
+  spec.add_development_dependency 'vterm', '>= 0.0.5' if is_unix
   spec.add_development_dependency 'yamatanooroti', '>= 0.0.6'
   spec.add_development_dependency "rake"
 end