Add static libiconv linking for gettext

Author: ychin

.github/actions/universal-package/action.yml

@@ -48,6 +48,7 @@ runs:
           # We also manually depend on GNU libiconv as Apple iconv is broken since macOS 14. This is necessary as MacVim
           # itself it built against it and we need both to match.
           sed -i.bak '/^[[:blank:]]*def install$/i\'$'\n  depends_on "libiconv"\n' ${formula}.rb
+          sed -i.bak '/^[[:blank:]]*def install$/a\'$'\n    ENV["LIBS"] = "'$(brew --prefix)$'/opt/libiconv/lib/libiconv.a"\n' ${formula}.rb
         fi
 
         # Homebrew requires formula files to be placed in taps and disallows