- `swig` is a build tool so it likely goes to `nativeBuildInputs`,
not `buildInputs`
- `patchPhase` should not be overridden, use `postPatch` instead
- `configureFlags` and `installFlags` cannot contain spaces,
break-up arguments to reflect that they are indeed without spaces
- `substituteStream()`: WARNING: pattern
`libdir='/build/unbound-1.13.1/lib/python3.9/site-packages'`
doesn't match anything in file `_unbound.la`
Also checked with `strings`, the correct path is present in the binary
fcff510efb