girepository: Update gir-compiler and use it to compile GIRs
Builds on !3797 (merged) to support !3746 (merged)
Adapt gir-compiler sources to compile against the updated libgirepository that is included with GLib.
This also renames "g-ir-compiler" to "gir-compiler" to avoid overwriting the existing binary and to simplify the binary name going forward.
Open questions
- What to name the binary
The previous suggestion was g-ir-compiler2
but I would be in favor of using this opportunity to make the binary name more obvious/clear: gir-compiler
, gir-compile
, gircompile
, girc
, etc.
- Do we want to keep the "sanity check" that hardcodes current blob sizes?