8a86fb78235b build: set GNU17 for lemon compilation Link: https://github.com/openwrt/openwrt/pull/18525 (cherry picked from commit 891c8244f2b346b00190d25bd6970cf755a4aaa6) Link: https://github.com/openwrt/openwrt/pull/18581 Signed-off-by: Robert Marko <robimarko@gmail.com>