tools/bootconfig: allow overriding CFLAGS assignment Allow overriding the CFLAGS assignment so that the user can pass in an outside value. Link: https://lore.kernel.org/all/20250328183858.1417835-2-bmasney@redhat.com/ Signed-off-by: Brian Masney <bmasney@redhat.com> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>