From the commit message:
There are occasions where one may not wish to build the introspection data, or is unable to do so, such as during a cross-compilation scenario.
This adds a configure time option to disable building introspection data and improves the check for G-I to make it optional depending on whether we really want to build the introspection data, and to just disable building the introspection during a cross-build scenario, like what GTK does.
This issue surfaced when attempting to cross-build amtk for ARM64 (aarch64) Windows on an x64 Windows system. It is currently not possible to build g-ir-scanner for ARM64 Windows since there is no Python release for ARM64.
With blessings, thank you!