[Fontconfig] check font-file for real SmallCaps support

[Werner LEMBERG]

>> I want to check if a font (e.g. FreeSans) support real small caps.
>> I checked with XeTeX that FreeSans does support it.
>
> That is not feasible to check with fontconfig. you need to use
> FreeType and Harfbuzz for convenience to see if fonts has smcp
> feature in GSUB.

Actually, this demand is not unreasonable.  I would even say that
fontconfig should be extended to report OpenType capabilities.


    Werner