[DRE-maint] Bug#892181: ruby-ncurses fails to load with Ruby 2.5

[Adrian Bunk]

Package: ruby-ncurses
Version: 1.4.9-1
Severity: serious
Control: affects -1 src:sup-mail

https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/sup-mail.html

...
RUBYLIB=/build/1st/sup-mail-0.22.1/debian/sup-mail/usr/lib/ruby/vendor_ruby:. GEM_PATH=debian/sup-mail/usr/share/rubygems-integration/all:/var/lib/gems/2.5.0:/usr/lib/x86_64-linux-gnu/rubygems-integration/2.5.0:/usr/share/rubygems-integration/2.5.0:/usr/share/rubygems-integration/all ruby2.5 debian/ruby-tests.rb
/usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require': /usr/lib/x86_64-linux-gnu/ruby/vendor_ruby/2.5.0/ncursesw_bin.so: undefined symbol: menu_fore - /usr/lib/x86_64-linux-gnu/ruby/vendor_ruby/2.5.0/ncursesw_bin.so (LoadError)