[PATCH] fix in6_pktinfo build issue on Linux

From http://roy.marples.name/projects/dhcpcd/vpatch?from=e05490e2d12d03b1&to=c32714545158ca83

Give up on _BSD_SOURCE and use _GNU_SOURCE for Linux. This is requires for
newer Linux headers as there is no easy way to get at the in6_pktinfo
structure, so we have to fallback to the glibc variant which requires
_GNU_SOURCE being set.  This does have the advantage of no longer sprinkling
_GNU_SOURCE around and no longer having to cast ipi.ipi_ifindex but may
break compile on older Linux.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
--

Index: common.c
==================================================================
--- a/common.c
+++ b/common.c
@@ -23,15 +23,10 @@
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
-/* Needed define to get at getline for glibc and FreeBSD */
-#ifndef _GNU_SOURCE
-#  define _GNU_SOURCE
-#endif
-
 #ifdef __APPLE__
 #  include <mach/mach_time.h>
 #  include <mach/kern_return.h>
 #endif
 

Index: configure
==================================================================
--- a/configure
+++ b/configure
@@ -358,27 +358,25 @@
 	echo "There is no fork"
 	echo "CPPFLAGS+=	-DTHERE_IS_NO_FORK" >>$CONFIG_MK
 fi
 
 case "$OS" in
-kfreebsd*)
+freebsd*|kfreebsd*)
 	echo "CPPFLAGS+=	-D_GNU_SOURCE" >>$CONFIG_MK
 	echo "DHCPCD_SRCS+=	if-bsd.c" >>$CONFIG_MK
 	;;
 linux*)
-	echo "CPPFLAGS+=	-D_BSD_SOURCE -D_XOPEN_SOURCE=700" >>$CONFIG_MK
+	echo "CPPFLAGS+=	-D_GNU_SOURCE" >>$CONFIG_MK
 	# Large File Support, should be fine for 32-bit systems.
 	# But if this is the case, why is it not set by default?
 	echo "CPPFLAGS+=	-D_FILE_OFFSET_BITS=64" >>$CONFIG_MK
 	echo "CPPFLAGS+=	-D_LARGEFILE_SOURCE" >>$CONFIG_MK
 	echo "CPPFLAGS+=	-D_LARGEFILE64_SOURCE" >>$CONFIG_MK
-	# glibc-2.20
-	echo "CPPFLAGS+=	-D_DEFAULT_SOURCE" >>$CONFIG_MK
 	echo "DHCPCD_SRCS+=	if-linux.c" >>$CONFIG_MK
 	# for RTM_NEWADDR and friends
-	echo "#include <asm/types.h> /* fix broken headers */" >>$CONFIG_H
-	echo "#include <linux/rtnetlink.h>" >>$CONFIG_H
+	echo "#include		<asm/types.h> /* fix broken headers */" >>$CONFIG_H
+	echo "#include		<linux/rtnetlink.h>" >>$CONFIG_H
 	;;
 qnx*)
 	echo "CPPFLAGS+=	-D__EXT" >>$CONFIG_MK
 	echo "DHCPCD_SRCS+=	if-bsd.c" >>$CONFIG_MK
 	;;
@@ -592,11 +590,10 @@
 fi
 
 if [ -z "$GETLINE" ]; then
 	printf "Testing for getline ... "
 	cat <<EOF >_getline.c
-#define _GNU_SOURCE
 #include <stdio.h>
 int main(void) {
 	char *buf = NULL;
 	size_t n = 0;
 	getline(&buf, &n, stdin);

Index: dhcp6.c
==================================================================
--- a/dhcp6.c
+++ b/dhcp6.c
@@ -1149,11 +1149,11 @@
 		return -1;
 	cm->cmsg_level = IPPROTO_IPV6;
 	cm->cmsg_type = IPV6_PKTINFO;
 	cm->cmsg_len = CMSG_LEN(sizeof(pi));
 	memset(&pi, 0, sizeof(pi));
-	pi.ipi6_ifindex = CAST_IPI6_IFINDEX(ifp->index);
+	pi.ipi6_ifindex = ifp->index;
 	memcpy(CMSG_DATA(cm), &pi, sizeof(pi));
 
 	if (sendmsg(ctx->dhcp_fd, &ctx->sndhdr, 0) == -1) {
 		logger(ifp->ctx, LOG_ERR,
 		    "%s: %s: sendmsg: %m", ifp->name, __func__);

Index: eloop.c
==================================================================
--- a/eloop.c
+++ b/eloop.c
@@ -23,13 +23,10 @@
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
-/* Needed for ppoll(2) */
-#define _GNU_SOURCE
-
 #include <sys/time.h>
 
 #include <errno.h>
 #include <limits.h>
 #include <signal.h>

Index: ipv6.h
==================================================================
--- a/ipv6.h
+++ b/ipv6.h
@@ -27,18 +27,12 @@
 
 #ifndef IPV6_H
 #define IPV6_H
 
 #include <sys/uio.h>
-
 #include <netinet/in.h>
 
-#if defined(__linux__) && defined(__GLIBC__)
-#  define _LINUX_IN6_H
-#  include <linux/ipv6.h>
-#endif
-
 #include "config.h"
 #include "dhcpcd.h"
 
 #define ALLROUTERS "ff02::2"
 
Index: ipv6nd.c
==================================================================
--- a/ipv6nd.c
+++ b/ipv6nd.c
@@ -293,11 +293,11 @@
 		return;
 	cm->cmsg_level = IPPROTO_IPV6;
 	cm->cmsg_type = IPV6_PKTINFO;
 	cm->cmsg_len = CMSG_LEN(sizeof(pi));
 	memset(&pi, 0, sizeof(pi));
-	pi.ipi6_ifindex = CAST_IPI6_IFINDEX(ifp->index);
+	pi.ipi6_ifindex = ifp->index;
 	memcpy(CMSG_DATA(cm), &pi, sizeof(pi));
 
 	logger(ifp->ctx, LOG_DEBUG,
 	    "%s: sending Router Solicitation", ifp->name);
 	if (sendmsg(ctx->nd_fd, &ctx->sndhdr, 0) == -1) {