[BUILD] undefined reference to void openvdb::v9_0::tools::dilateActiveValues (USE_EXPLICIT_INSTANTIATION)

### Environment
**Operating System:** (Linux Debian bullseye)
**Version / Commit SHA:** ( VDB 9.0.0)
**CMake Version:** ( 3.22)
**Compiler:** ( gcc 10)

### Describe the problem

I can no longer build openvdb using the export mechanism on UNIX. In the past I was able to use:

```
CFLAGS+=$(CPPFLAGS) -fvisibility=hidden -fvisibility-inlines-hidden
CXXFLAGS+=$(CPPFLAGS) -fvisibility=hidden -fvisibility-inlines-hidden
```

This is no longer the case. This is an issue at least on Debian arch, since using the above flags, greatly reduce the number of symbols being exported. Please provide a patch to fix this compilation issue.

### To Reproduce

Download release 9.0.0, and extract:
```
$ export CXXFLAGS='-fvisibility=hidden -fvisibility-inlines-hidden'
$ mkdir build
$ cd build
$ cmake -DOPENVDB_BUILD_VDB_LOD:BOOL=TRUE ..
$ make vdb_lod
```