dhcpcd: fix ipv6 related compile failure

Add '-D_GNU_SOURCE' to gain missing struct in6_pktinfo definition.

Fixes [1]:

ipv6.h:211:41: error: invalid application of 'sizeof' to incomplete type 'struct in6_pktinfo'

  unsigned char sndbuf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
                                         ^
ipv6.h:195:38: error: invalid application of 'sizeof' to incomplete type 'struct in6_pktinfo'
 #define IP6BUFLEN (CMSG_SPACE(sizeof(struct in6_pktinfo)) + \
                                      ^

ipv6.h:214:23: note: in expansion of macro 'IP6BUFLEN'
unsigned char rcvbuf[IP6BUFLEN];

[1] http://autobuild.buildroot.net/results/523/523858fb930e74fe28f24989ff0697693b5fdd67

---
 package/dhcpcd/dhcpcd.mk | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index 4056351..756a660 100644
@@ -20,8 +20,8 @@ endif
 
 define DHCPCD_CONFIGURE_CMDS
 	(cd $(@D); \
-	$(TARGET_CONFIGURE_OPTS) ./configure \
-		--os=linux \
+	$(TARGET_CONFIGURE_OPTS) CFLAGS="$(TARGET_CFLAGS) -D_GNU_SOURCE" \
+		./configure --os=linux \
 		$(DHCPCD_CONFIG_OPTS) )
 endef
 

2.1.4

Bernd sent a similar patch:

http://patchwork.ozlabs.org/patch/462596/

But this is imho nicer than patching the source, so I've applied this and marked that patch as superseed.

Thanks both!

Bye, Peter Korsgaard