build: avoid symbol namespace pollution

As of f40eabb01 (add pkt_buff and protocol helper functions)
libnetfilter_queue accidentally exports the internal function named
'checksum'.  This is a bit too generic and may cause crashes with
applications that worked fine before.

This patch makes the functions checksum, checksum_tcpudp_ipv4 and
checksum_tcpudp_ipv6 local by building with fvis-hidden and adding
EXPORTs for the legacy api calls and the ones that seem to have missing
EXPORT tags (mainly pktbuff api).

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/Make_global.am b/Make_global.am
index 9bc8ea1..91da5da 100644
--- a/Make_global.am
+++ b/Make_global.am
@@ -1,2 +1,2 @@
 AM_CPPFLAGS = -I${top_srcdir}/include ${LIBNFNETLINK_CFLAGS} ${LIBMNL_CFLAGS}
-AM_CFLAGS = -Wall
+AM_CFLAGS = -Wall ${GCC_FVISIBILITY_HIDDEN}