BUILD: acl: use __fallthrough in parse_acl_expr()
This avoids two build warnings when preprocessing happens before compiling
with gcc >= 7.
diff --git a/src/acl.c b/src/acl.c
index 15ca766..84cb0f0 100644
--- a/src/acl.c
+++ b/src/acl.c
@@ -601,7 +601,7 @@
case STD_OP_GT:
value++; /* gt = ge + 1 */
- /* fall through */
+ __fallthrough;
case STD_OP_GE:
if (expr->pat.parse == pat_parse_int)
@@ -614,7 +614,7 @@
case STD_OP_LT:
value--; /* lt = le - 1 */
- /* fall through */
+ __fallthrough;
case STD_OP_LE:
if (expr->pat.parse == pat_parse_int)