Sigh. I think that is totally my fault.
I submitted a bugreport for ArchLinux with an updated PKGBUILD for Sigil 0.9.0 -- it included the USE_SYSTEM_LIBS option.
I guess they only
just realized Sigil even had bundled libs.
Which is not really anyone's fault.
At least, now that Sigil includes documentation for that feature, which IIRC was so totally not the case when they packaged Sigil, on account of there was no BuildingOnLinux.md and even that didn't mention it until prompted by my mostly-unrelated PR.
But thanks for doing what you do for making it easier

I really do appreciate it.
P.S. I don't
like the launch scrip myself. But I accept it as a necessity, one which serves a valid purpose.