OpenEXR 3 added an extern "C" LUT for Half. The default configuration wasn't using it, but exporting it means that because the type of the lookup table is namespaced, we can end up with conflicts if two namespaced versions of OpenVDB are compiled together, or OpenVDB with any OpenEXR external library.
This explicitly disables the creation of the Half LUT to avoid this.
OpenEXR 3 added an extern "C" LUT for Half. The default configuration wasn't using it, but exporting it means that because the type of the lookup table is namespaced, we can end up with conflicts if two namespaced versions of OpenVDB are compiled together, or OpenVDB with any OpenEXR external library.
This explicitly disables the creation of the Half LUT to avoid this.