rb_econv_prepare_opts 2684 ext/zlib/zlib.c 	gz->ecflags = rb_econv_prepare_opts(opts, &opts);
rb_econv_prepare_opts  221 include/ruby/encoding.h int rb_econv_prepare_opts(VALUE opthash, VALUE *ecopts);
rb_econv_prepare_opts 4116 io.c                   ecflags = rb_econv_prepare_opts(opthash, &ecopts);
rb_econv_prepare_opts 6974 io.c                   ecflags = rb_econv_prepare_opts(opt, &ecopts);
rb_econv_prepare_opts 6987 io.c                           ecflags = rb_econv_prepare_opts(opt, &ecopts);
rb_econv_prepare_opts 2529 transcode.c                ecflags = rb_econv_prepare_opts(opt, &ecopts);
rb_econv_prepare_opts 2756 transcode.c            ecflags = rb_econv_prepare_opts(opthash, &ecopts);