The default font should at least support part of the Romanian diatrics, but I'm not entierly sure about that... Because there's two way to display those diatrics, and it depends on the fonts (either you got a glyph for the basic latin letter, and a glyph for the diatric, and the software combines the two, or, and it's the more widespread method, because of compatiblity issues, you got a single glyph for each letter+diatric combinations).
Bottom line: I'd have to check to be sure.
Do you have an example that I could try? (With a screenshot of what it should look like, if possible
)