fix header checking, add dist header

Signed-off-by: Luotao Fu <l.fu@pengutronix.de>

configure.ac

@@ -66,8 +66,8 @@ AC_CHECK_HEADERS([	\
 	unistd.h	\
 	utime.h		\
 	net/if.h	\
-	linux/netlink.h \
-	linux/rtnetlink.h \
+	linux/netlink.h,,,[linux/socket.h] \
+	linux/rtnetlink.h,,,[linux/socket.h] \
 	])
 
 

include/GNUmakefile.am

@@ -2,7 +2,8 @@ noinst_HEADERS = \
 	libsocketcan-nlstuff.h
 
 nobase_include_HEADERS = \
-	socketcan_netlink.h
+	socketcan_netlink.h \
+	can/netlink.h
 
 MAINTAINERCLEANFILES = \
 	libsocketcan-nl_config.h.in \