Make fallthrough explicit for libworker.c

The code currently doesn't compile with LLVM's `-Wimplicit-fallthrough` flag, but the attribute works for both GCC (>=7) and LLVM.

diff --git a/libunbound/libworker.c b/libunbound/libworker.c
index 5c75f61d8dcb2e1430d7b3d2bfeee65ec0a44fff..191aa0b278554e34c06385c6985a23e9680e46db 100644 (file)
--- a/libunbound/libworker.c
+++ b/libunbound/libworker.c
@@ -292,7 +292,7 @@ libworker_do_cmd(struct libworker* w, uint8_t* msg, uint32_t len)
                        log_err("unknown command for bg worker %d", 
                                (int)context_serial_getcmd(msg, len));
                        /* and fall through to quit */
-                       /* fallthrough */
+                       __attribute__((fallthrough));
                case UB_LIBCMD_QUIT:
                        free(msg);
                        comm_base_exit(w->base);