Hide all symbols in the gdk-pixbuf plugin. (#566)
Hide all symbols in the gdk-pixbuf plugin. (#566)

This will prevent potential runtime conflicts with other libraries that
also use skcms.
libjxl/libjxl,libjxl/libjxl,libjxl/libjxl,libjxl/libjxl,libjxl/libjxl,libjxl/libjxl,libjxl/libjxl,libjxl/libjxl