but still enable it by default even if GDAL_BUILD_OPTIONAL_DRIVERS=OFF
Creation side is still available, but Open() not
Also enable GTI driver to be separately enabled/disabled, and buildable as a plugin (if built as a plugin, gdaladdo --partial-refresh-from-source-timestamp won't work)
coverage: 69.42%. remained the same
when pulling 3a5c02e8c170bba1384da17938e97ecf0f3eb756 on rouault:vrt_optional
into 9f8fea14708957b26dff299f32ef74cf56a50c52 on OSGeo:master.
but still enable it by default even if GDAL_BUILD_OPTIONAL_DRIVERS=OFF
Creation side is still available, but Open() not
Also enable GTI driver to be separately enabled/disabled, and buildable as a plugin (if built as a plugin, gdaladdo --partial-refresh-from-source-timestamp won't work)
Derived driver: make it optional