ruby-build 20210510 * Join *_OPTS variables after *_OPTS_ARRAY variables This for instance allows `RUBY_CONFIGURE_OPTS` to override what's set by the definition. For instance `enable_shared` can be disabled with `RUBY_CONFIGURE_OPTS='--disable-shared'` * Do not append `--enable-shared` if RUBY_CONFIGURE_OPTS include `--disable-shared`