[source] libpcap: add optional netfilter support

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/fdfde3eb21dbc55cdaf4fed6b374ce6cfc704e42

commit fdfde3eb21dbc55cdaf4fed6b374ce6cfc704e42
Author: Martin Schiller <mschiller at tdt.de>
AuthorDate: Mon Feb 20 06:27:41 2017 +0100

    libpcap: add optional netfilter support
    
    This is needed to use the nflog interface with tcpdump
    
    Signed-off-by: Martin Schiller <mschiller at tdt.de>
---
 package/libs/libpcap/Config.in | 4 ++++
 package/libs/libpcap/Makefile  | 7 +++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/package/libs/libpcap/Config.in b/package/libs/libpcap/Config.in
index 05f45f4..1159927 100644
--- a/package/libs/libpcap/Config.in
+++ b/package/libs/libpcap/Config.in
@@ -10,4 +10,8 @@ config PCAP_HAS_BT
 	depends on BROKEN
 	default n
 
+config PCAP_HAS_NETFILTER
+	bool "Include netfilter support"
+	default n
+
 endmenu
diff --git a/package/libs/libpcap/Makefile b/package/libs/libpcap/Makefile
index d3360d2..4d0ce40 100644
--- a/package/libs/libpcap/Makefile
+++ b/package/libs/libpcap/Makefile
@@ -48,9 +48,12 @@ TARGET_CFLAGS += \
 
 CONFIGURE_VARS += \
 	ac_cv_linux_vers=$(LINUX_VERSION) \
-	ac_cv_header_libusb_1_0_libusb_h=no \
-	ac_cv_netfilter_can_compile=no
+	ac_cv_header_libusb_1_0_libusb_h=no
 
+ifeq ($(CONFIG_PCAP_HAS_NETFILTER),)
+CONFIGURE_VARS += \
+	ac_cv_netfilter_can_compile=no
+endif
 
 CONFIGURE_ARGS += \
 	--enable-shared \