vips: update to 8.16.0, use modules.

[yoshiyoshyosh]

Testing the changes

• I tested the changes in this PR: YES
  • only on my machine, which is x86_64_glibc. I can't test if the cross-compiling gobject modules thing is correct...

Local build testing

• x86-64_glibc
• aarch64_musl (crossbuild)

[icp1994]

I think the convention is to use ${version%.*} instead of introducing another variable which needs to be updated after every major version bump.

[yoshiyoshyosh]

I think the convention is to use ${version%.*} instead of introducing another variable which needs to be updated after every major version bump.

good point, dunno why I didn't think of that