RHEL8 compatibility

[Robert-André Mauchin]

Hello,

The RHEL8 kernel (4.18) contains backported changes that make it act more like
a > 4.7 kernel. As such src/compat/compat.h need to be patched to handle
RHEL8 special case.

We are currently using this patch in RPMFusion EPEL8 branch:

--- a/WireGuard-0.0.20190702/src/compat/compat.h
+++ b/WireGuard-0.0.20190702/src/compat/compat.h
@@ -79,18 +79,6 @@
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(4, 3, 0) && !defined(ISRHEL7)
 #define ipv6_dst_lookup(a, b, c, d) ipv6_dst_lookup(b, c, d)
-#endif
-
-#if (LINUX_VERSION_CODE == KERNEL_VERSION(4, 4, 0) || \
-    (LINUX_VERSION_CODE < KERNEL_VERSION(4, 3, 5) && LINUX_VERSION_CODE >= KERNEL_VERSION(4, 2, 0)) || \
-    (LINUX_VERSION_CODE < KERNEL_VERSION(4, 1, 17) && LINUX_VERSION_CODE > KERNEL_VERSION(3, 19, 0)) || \
-    (LINUX_VERSION_CODE < KERNEL_VERSION(3, 18, 27) && LINUX_VERSION_CODE >= KERNEL_VERSION(3, 17, 0)) || \
-    (LINUX_VERSION_CODE < KERNEL_VERSION(3, 16, 8) && LINUX_VERSION_CODE >= KERNEL_VERSION(3, 15, 0)) || \
-    (LINUX_VERSION_CODE < KERNEL_VERSION(3, 14, 40) && LINUX_VERSION_CODE >= KERNEL_VERSION(3, 13, 0)) || \
-    (LINUX_VERSION_CODE < KERNEL_VERSION(3, 12, 54))) && !defined(ISUBUNTU1404)
-#include <linux/if.h>
-#include <net/ip_tunnels.h>
-#define IP6_ECN_set_ce(a, b) IP6_ECN_set_ce(b)
 #endif
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 12, 0) && IS_ENABLED(CONFIG_IPV6) && !defined(ISRHEL7)


Could you please define a ISRHEL8 to handle this?