We use errno, so we need to include <errno.h>.

Change-Id: Ic6d88c508594aa9daf36bd0a6a9f2fe4f0db71bd
Reviewed-on: https://code.wireshark.org/review/29230
Reviewed-by: Guy Harris <guy@alum.mit.edu>

caputils/capture-pcap-util.c

@@ -18,6 +18,7 @@
 #include <stdio.h>
 #include <limits.h>
 #include <string.h>
+#include <errno.h>
 
 #include <sys/types.h>