libpcap: bump to version 1.8.1

Drop upstream patch.

Also remove ac_cv_linux_vers caching since this check was remove in upstream
commit f3e011b18c55ae.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/libpcap/0002-configure.in-fix-detect-of-if_bonding.h-on-uclinux.patch

@@ -1,30 +0,0 @@
-From 5b8dc4eaeab60d5effc33055e5bce9ac0d98d339 Mon Sep 17 00:00:00 2001
-From: Baruch Siach <baruch@tkos.co.il>
-Date: Tue, 2 Jun 2015 21:39:15 +0300
-Subject: [PATCH] configure.in: fix detect of if_bonding.h on uclinux
-
-noMMU Linux (uClinux) is also Linux
-
-Upstream status: https://github.com/the-tcpdump-group/libpcap/pull/440
-
-Signed-off-by: Baruch Siach <baruch@tkos.co.il>
----
- configure.in | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
-diff --git a/configure.in b/configure.in
-index be4b29e2f8ba..31287d0dbe61 100644
---- a/configure.in
-+++ b/configure.in
-@@ -149,7 +149,7 @@ struct rtentry;
- fi
- 
- case "$host_os" in
--linux*)
-+linux*|uclinux*)
- 	AC_CHECK_HEADERS(linux/sockios.h linux/if_bonding.h,,,
- 	[
- #include <sys/socket.h>
--- 
-2.1.4
-

package/libpcap/libpcap.hash

@@ -1,2 +1,2 @@
 # Locally calculated after checking pgp signature
-sha256	7ad3112187e88328b85e46dce7a9b949632af18ee74d97ffc3f2b41fe7f448b0	libpcap-1.7.4.tar.gz
+sha256	673dbc69fdc3f5a86fb5759ab19899039a8e5e6c631749e48dcd9c6f0c83541e	libpcap-1.8.1.tar.gz

package/libpcap/libpcap.mk

@@ -4,17 +4,14 @@
 #
 ################################################################################
 
-LIBPCAP_VERSION = 1.7.4
+LIBPCAP_VERSION = 1.8.1
 LIBPCAP_SITE = http://www.tcpdump.org/release
 LIBPCAP_LICENSE = BSD-3c
 LIBPCAP_LICENSE_FILES = LICENSE
 LIBPCAP_INSTALL_STAGING = YES
 LIBPCAP_DEPENDENCIES = zlib host-flex host-bison
 
-# We're patching configure.in
-LIBPCAP_AUTORECONF = YES
 LIBPCAP_CONF_ENV = \
-	ac_cv_linux_vers=2 \
 	ac_cv_header_linux_wireless_h=yes \
 	CFLAGS="$(LIBPCAP_CFLAGS)"
 LIBPCAP_CFLAGS = $(TARGET_CFLAGS)