iproute: build more easily on Android

iproute2 contains a bunch of kernel headers, including uapi ones.
Android's libc uses uapi headers almost directly, and uses a
script to fix kernel types that don't match what userspace
expects.

For example: https://issuetracker.google.com/36987220 reports
that our struct ip_mreq_source contains "__be32 imr_multiaddr"
rather than "struct in_addr imr_multiaddr". The script addresses
this by replacing the uapi struct definition with a #include
<bits/ip_mreq.h> which contains the traditional userspace
definition.

Unfortunately, when we compile iproute2, this definition
conflicts with the one in iproute2's linux/in.h.

Historically we've just solved this problem by running "git rm"
on all the iproute2 include/linux headers that break Android's
libc.  However, deleting the files in this way makes it harder to
keep up with upstream, because every upstream change to
an include file causes a merge conflict with the delete.

This patch fixes the problem by moving the iproute2 linux headers
from include/linux to include/uapi/linux.

Tested: compiles on ubuntu trusty (glibc)

Signed-off-by: Elliott Hughes <enh@google.com>
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>

Makefile

@@ -46,7 +46,7 @@ CCOPTS = -O2
 WFLAGS := -Wall -Wstrict-prototypes  -Wmissing-prototypes
 WFLAGS += -Wmissing-declarations -Wold-style-definition -Wformat=2
 
-CFLAGS := $(WFLAGS) $(CCOPTS) -I../include $(DEFINES) $(CFLAGS)
+CFLAGS := $(WFLAGS) $(CCOPTS) -I../include -I../include/uapi $(DEFINES) $(CFLAGS)
 YACCFLAGS = -d -t -v
 
 SUBDIRS=lib ip tc bridge misc netem genl tipc devlink rdma man