void fcft_text_run_destroy(struct fcft_text_run *run);
fcft_text_run_destroy() frees the fcft_text_run object run, which must have been created with fcft_text_run_rasterize().
Note that it is ok to call fcft_destroy() on the font object that was used to rasterize the text-run, before freeing the text-run itself. I.e. applications may cache text-runs beyond the life time of the font object.
run may be NULL, in which case fcft_text_run_destroy() is a no-op.