[HarfBuzz] Guessing the script of a string.

[Eduardo Castiñeyra]

>> HarfBuzz should do this automatically if you don't explicitly set the
>> script of a hb_buffer. This seems to work fine for me here, at least.

 > Correct.

 > The way to get to that functionality more directly is to call
 > hb_unicode_funcs_get_default(), and with the returned object call
 > hb_unicode_get_script().  That works on a single Unicode character.

 > behdad

I have been reviewing the code, and I don't find a relationship between 
codepoint ranges and all the unicode scripts in any part of the code. 
The hb_unicode_get_script_nil function, which seems to be the internal 
one, is empty. Does it mean that one needs icu or glib to compile harfbuzz?

Would it be that hard to make a lookup a table with Unicode ranges and 
scripts to not having to use external libraries? Or isn't it that easy?