The accents are taken from the Roboto Regular font (Apache 2.0), added
the dotted circle and exported with FontForge.
The argument to FontForge's Import function are changed, the fifth
argument controls the accuracy and needed to be lowered otherwise the
grave accent wouldn't be rendered at all.
Keep the glyphs in SVG format and build the font using a FontForge
script.
A part of the previous font is kept because the sources is lost.
This adds a new dependency to the build system, fontforge.
