introspection option

[Thomas Klausner <wiz%NetBSD.org@localhost>]

Hi!

Some packages in pkgsrc have an introspection option that basically
adds a gobject-introspection build dependency and installs more files
(*.typelib, *.gir).

However, this is not consistently applied. For example, PR 56755
complains that when introspection is disabled for harfbuzz, pango
won't build (because it unconditionally enables introspection).

We could of course fix pango to honor the global introspection option
(and probably would need to fix some pango dependencies next), but
before doing that I wonder what the rationale is for turning it off in
the first place?

The build dependency doesn't look heavy enough for me to make this
option worth the hassle.

Insights welcome!
 Thomas