Comment 3 for bug 58519

Additional debugging has revealed that the culprit font, if it's the font's
fault, is DejaVuSans.ttf

Adding the following to the end of _cairo_ft_unscaled_font_set_scale

if(error != 0){
    printf("About to blow...\n");
    printf("\"%s\"\n", unscaled->filename);
}
    assert (error == 0);

Produced the following:

About to blow...
About to blow...
"/usr/share/fonts/truetype/ttf-dejavu/DejaVuSans.ttf"
"/usr/share/fonts/truetype/ttf-dejavu/DejaVuSans.ttf"

Kip