Test size/align of structs
diff --git a/src/lib.rs b/src/lib.rs
index e9a6bef..46a53d0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -334,7 +334,8 @@
                 }
                 #[repr(C)]
                 #[derive(Copy, Clone)] pub struct in6_addr {
-                    pub s6_addr: [u16; 8]
+                    pub s6_addr: [u16; 8],
+                    __align: [u32; 0],
                 }
                 #[repr(C)]
                 #[derive(Copy, Clone)] pub struct ip_mreq {
@@ -897,7 +898,8 @@
                 }
                 #[repr(C)]
                 #[derive(Copy, Clone)] pub struct in6_addr {
-                    pub s6_addr: [u16; 8]
+                    pub s6_addr: [u16; 8],
+                    __align: [u32; 0],
                 }
                 #[repr(C)]
                 #[derive(Copy, Clone)] pub struct ip_mreq {
@@ -1258,7 +1260,8 @@
                 }
                 #[repr(C)]
                 #[derive(Copy, Clone)] pub struct in6_addr {
-                    pub s6_addr: [u16; 8]
+                    pub s6_addr: [u16; 8],
+                    __align: [u32; 0],
                 }
                 #[repr(C)]
                 #[derive(Copy, Clone)] pub struct ip_mreq {
@@ -1544,7 +1547,8 @@
                 }
                 #[repr(C)]
                 #[derive(Copy, Clone)] pub struct in6_addr {
-                    pub s6_addr: [u16; 8]
+                    pub s6_addr: [u16; 8],
+                    __align: [u32; 0],
                 }
                 #[repr(C)]
                 #[derive(Copy, Clone)] pub struct ip_mreq {
@@ -1775,7 +1779,8 @@
                 }
                 #[repr(C)]
                 #[derive(Copy, Clone)] pub struct in6_addr {
-                    pub s6_addr: [u16; 8]
+                    pub s6_addr: [u16; 8],
+                    __align: [u32; 0],
                 }
                 #[repr(C)]
                 #[derive(Copy, Clone)] pub struct ip_mreq {
@@ -2233,7 +2238,8 @@
 
                 #[repr(C)]
                 #[derive(Copy, Clone)] pub struct in6_addr {
-                    pub s6_addr: [u16; 8]
+                    pub s6_addr: [u16; 8],
+                    __align: [u32; 0],
                 }
 
                 #[repr(C)]