Is this another casualty of Pango 1.44 dropping support for bitmap fonts?
That's very well possible. Helvetica is only available as bitmap font on the systems I tested it (NetBSD and Solaris). When I use e.g. "Luxi Sans" on NetBSD, the fonts are rendered okay, this font is available as Type 1 and TTF. When I use "Utopia", unfortunately a bitmap version of that font is used instead of the Type 1 version. So at the moment only vector fonts seem to work that don't also have a bitmap variant.
-- Jörn Clausen Plattformen & Serverdienste BITS - Bielefelder IT-Servicezentrum https://www.uni-bielefeld.de/bits