Use compiler tests to determine how to define _U_.

One less thing that has to be done in autotools and CMake.

1 files changed, 1 insertions, 0 deletions

diff --git a/pcap-int.h b/pcap-int.h
index d1ea4a15..516b49c3 100644
--- a/pcap-int.h
+++ b/pcap-int.h
@@ -38,6 +38,7 @@
 
 #include <pcap/pcap.h>
 
+#include "varattrs.h"
 #include "fmtutils.h"
 
 /*