From d67e0b6d39b4b4457f4d04dfa5606c35139b9ccc Mon Sep 17 00:00:00 2001
From: Nicolas Williams <nico@twosigma.com>
Date: Mon, 5 Jan 2026 19:16:19 -0600
Subject: [PATCH] cf: clang -Wimplicit-fallthrough for flex code

---
 cf/wflags.m4 | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/cf/wflags.m4 b/cf/wflags.m4
index efd88bf66..4328f9ee3 100644
--- a/cf/wflags.m4
+++ b/cf/wflags.m4
@@ -30,9 +30,11 @@ if test -z "$WFLAGS" -a "$GCC" = "yes"; then
 
   # Replace GCC-specific warning flags with Clang equivalents
   if test "$rk_CLANG" = yes; then
+    # -Wimplicit-fallthrough removed: flex-generated code triggers it and can't be fixed
     wflags=`echo "$wflags" | sed -e 's/-Wdiscarded-qualifiers/-Wignored-qualifiers/g' \
                                   -e 's/ -Wunused-but-set-variable//g' \
-                                  -e 's/ -Wunused-const-variable//g'`
+                                  -e 's/ -Wunused-const-variable//g' \
+                                  -e 's/ -Wimplicit-fallthrough//g'`
   fi
 
   WFLAGS="$wflags $dwflags"