passt: Fix build with gcc 7, use std=c99, enable some more Clang checkers

Unions and structs, you all have names now.

Take the chance to enable bugprone-reserved-identifier,
cert-dcl37-c, and cert-dcl51-cpp checkers in clang-tidy.

Provide a ffsl() weak declaration using gcc built-in.

Start reordering includes, but that's not enough for the
llvm-include-order checker yet.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/pasta.c b/pasta.c
index 3febfd5..c13743b 100644
--- a/pasta.c
+++ b/pasta.c
@@ -15,7 +15,6 @@
  * #syscalls:pasta geteuid getdents64 readlink setsid nanosleep clock_nanosleep
  */
 
-#define _GNU_SOURCE
 #include <sched.h>
 #include <stdio.h>
 #include <string.h>
@@ -36,6 +35,8 @@
 #include <net/ethernet.h>
 #include <sys/syscall.h>
 
+#include <linux/ipv6.h>
+
 #include "util.h"
 #include "passt.h"
 #include "netlink.h"