Fail to compile with new version of Harfbuzz

[Hugo Parente Lima]

A new version of pango and harfbuzz landed in Archlinux package repositories, when using then the generated bindings fail to compile, the problem seems to be on Harfbuzz, but Pango depends on Harfbuzz.

Broken versions:
Pango: 1.46.0
Harfbuzz: 2.7.1

Versions that work:
Pango: 1.44.7
Harfbuzz: 2.7.0

Test can be done with files under project sample directory:

$ crystal run gdk_window.cr 
There was a problem expanding macro 'require_gobject'

Code in macro 'require_gobject'

 7 | require_gobject("HarfBuzz", "0.0")
     ^
Called macro defined in lib/gobject/gobject.cr:25:1

 25 | macro require_gobject(namespace, version = nil)

Which expanded to:

 > 553 |   ###########################################
 > 554 | 
 > 555 |   union hb_var_int_t
                 ^
Error: expecting token 'CONST', not 'hb_var_int_t'
code 1