[PATCH] bootconfig: give the footer size static_assert a message

[Sasha Levin]

static_assert() without a message is a C23 feature, so clang warns:

  main.c:498:56: warning: '_Static_assert' with no message is a C23 extension [-Wc23-extensions]

Add a message.

Fixes: 6ed5e20466c79 ("bootconfig: Fix unaligned access when building footer")
Cc: stable@xxxxxxxxxxxxxxx
Assisted-by: LLM
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 tools/bootconfig/main.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/bootconfig/main.c b/tools/bootconfig/main.c
index 17d971d47f879..df05340358578 100644
--- a/tools/bootconfig/main.c
+++ b/tools/bootconfig/main.c
@@ -495,7 +495,8 @@ static int apply_xbc(const char *path, const char *xbc_path)
 	footer.size = htole32(size);
 	footer.csum = htole32(csum);
 	memcpy(footer.magic, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN);
-	static_assert(sizeof(footer) == BOOTCONFIG_FOOTER_SIZE);
+	static_assert(sizeof(footer) == BOOTCONFIG_FOOTER_SIZE,
+		      "bootconfig footer size mismatch");
 	memcpy(data + size, &footer, BOOTCONFIG_FOOTER_SIZE);
 
 	total_size = size + BOOTCONFIG_FOOTER_SIZE;
-- 
2.53.0