build: if `--enable-pcap` is `yes`, abort if libpcap is not found

If libpcap support has been explicitly requested, abort if it is not
available.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/configure.ac b/configure.ac
index 620cb34c8537d62075594625c721b208d915c38e..41eeb52b912121bf73f39c3f1318398a386bcc68 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -213,6 +213,12 @@ AS_IF([test "x$enable_pcap" != "xno"], [
       AC_MSG_RESULT([no])
     ])
 
+    AS_IF([test "x$libpcap_LIBS" = "x"], [
+      AS_IF([test "x$enable_pcap" = "xyes"], [
+        AC_MSG_ERROR([libpcap not found])
+      ])
+    ])
+
   ])
 
 ])