dyld: lazy symbol binding failed: Symbol not found: _libiconv_open

i run it for mac os x

dyld: lazy symbol binding failed: Symbol not found: _libiconv_open
  Referenced from: /Users/git/gitlab/vendor/bundle/ruby/2.3.0/gems/rugged-0.24.0/lib/rugged/rugged.bundle
  Expected in: flat namespace

dyld: Symbol not found: _libiconv_open
  Referenced from: /Users/git/gitlab/vendor/bundle/ruby/2.3.0/gems/rugged-0.24.0/lib/rugged/rugged.bundle
  Expected in: flat namespace

thank you