Typo
Combine the two if’s
Make writing outlines with Cairo actually work
Add an option for writing outlines directly
Add an option to use Pango for drawing glyph cells
Fix warning
I can make it an option and send a GitHub pull request. For my fonts the difference between using Freetype and Pango is the difference between not showing glyphs at all and showing them correctly. The dotted cirrcle is a feature for me as well (though it can be disable by putting a space before the marks), as it makes combining from non-compining marks clear and make it easy to see if the mark applies above or below the base.
It was introduced in Pango 1.37, released in May 2015 (based on the git tag).