pping: Guard local definitions of AF_* constants in pping_kern.c

The header files included from pping_kern.c include definitions of AF_INET
and AF_INET6, leading to warnings like:

pping_kern.c:25:9: warning: 'AF_INET' macro redefined [-Wmacro-redefined]
        ^
/usr/include/bits/socket.h:97:9: note: previous definition is here
        ^
pping_kern.c:26:9: warning: 'AF_INET6' macro redefined [-Wmacro-redefined]
        ^
/usr/include/bits/socket.h:105:9: note: previous definition is here
        ^
2 warnings generated.

Fix this by guarding the definitions behind suitable ifdefs.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>

Author: tohojo

pping/pping_kern.c

@@ -22,8 +22,12 @@
 #include "pping.h"
 #include "pping_debug_cleanup.h"
 
+#ifndef AF_INET
 #define AF_INET 2
+#endif
+#ifndef AF_INET6
 #define AF_INET6 10
+#endif
 #define MAX_TCP_OPTIONS 10
 
 // Mask for IPv6 flowlabel + traffic class -  used in fib lookup