"hintstyle" setting on fonts.conf seems to be ignored.
I understand it is impossible to set "rgba=rgb" and "hintstyle=hintslight" at the same time because of freetype restriction.
But even if "rgba=none", "hintstyle" setting is ignored.

A patch to fix this bug:
--- cairo-1.4.10/src/cairo-ft-font.c
+++ cairo-1.4.10/src/cairo-ft-font.c
@@@ -1404,7 +1616,7 @@
    options->base.subpixel_order = other->base.subpixel_order;
     }

-    if (options->base.hint_style == CAIRO_HINT_STYLE_DEFAULT)
+    if (other->base.hint_style != CAIRO_HINT_STYLE_DEFAULT)
    options->base.hint_style = other->base.hint_style;

     if (other->base.hint_style == CAIRO_HINT_STYLE_NONE)