[PATCH] linux-libc-headers: fix duplicate IFF_LOWER_UP DORMANT ECHO on musl

["André Draszik" <git@andred.net>]

From: André Draszik <adraszik@tycoint.com>

musl _does_ define IFF_LOWER_UP DORMANT ECHO so we should
prevent redefinition of these when on musl.

As per the included patch, this can be triggered by
(from connman 6to4.c):
    include <errno.h>
    include <stdio.h>
    include <stdlib.h>
    include <string.h>
    include <sys/socket.h>
    include <netinet/in.h>
    include <arpa/inet.h>
    include <net/if.h>
    include <linux/ip.h>
    include <linux/if_tunnel.h>
    include <linux/netlink.h>
    include <linux/rtnetlink.h>
    include <sys/ioctl.h>
    include <unistd.h>

In file included from ../git/src/6to4.c:34:0:
.../usr/include/linux/if.h:97:2: error: expected identifier before numeric constant
  IFF_LOWER_UP   = 1<<16, /* __volatile__ */
  ^

This is because at that time, IFF_LOWER_UP has been converted
to 0x10000 already:
enum net_device_flags {
 0x10000 = 1<<16,
 0x20000 = 1<<17,
 0x40000 = 1<<18,

};

By defining __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO
to 0, we avoid the duplicated definition.

Signed-off-by: André Draszik <adraszik@tycoint.com>
---
 ....h-musl-_does_-define-IFF_LOWER_UP-DORMAN.patch | 62 ++++++++++++++++++++++
 .../linux-libc-headers/linux-libc-headers_4.10.bb  |  1 +
 2 files changed, 63 insertions(+)
 create mode 100644 meta/recipes-kernel/linux-libc-headers/linux-libc-headers/0001-libc-compat.h-musl-_does_-define-IFF_LOWER_UP-DORMAN.patch

diff --git a/meta/recipes-kernel/linux-libc-headers/linux-libc-headers/0001-libc-compat.h-musl-_does_-define-IFF_LOWER_UP-DORMAN.patch b/meta/recipes-kernel/linux-libc-headers/linux-libc-headers/0001-libc-compat.h-musl-_does_-define-IFF_LOWER_UP-DORMAN.patch
new file mode 100644
index 0000000000..fd1bb9edb8
--- /dev/null
+++ b/meta/recipes-kernel/linux-libc-headers/linux-libc-headers/0001-libc-compat.h-musl-_does_-define-IFF_LOWER_UP-DORMAN.patch
@@ -0,0 +1,62 @@
+From 08a04c025395b0580913285045f2af36ee0985db Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Andr=C3=A9=20Draszik?= <adraszik@tycoint.com>
+Date: Thu, 15 Jun 2017 16:55:33 +0100
+Subject: [PATCH] libc-compat.h: musl _does_ define IFF_LOWER_UP DORMANT ECHO
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+To trigger this (from connman 6to4.c):
+    include <errno.h>
+    include <stdio.h>
+    include <stdlib.h>
+    include <string.h>
+    include <sys/socket.h>
+    include <netinet/in.h>
+    include <arpa/inet.h>
+    include <net/if.h>
+    include <linux/ip.h>
+    include <linux/if_tunnel.h>
+    include <linux/netlink.h>
+    include <linux/rtnetlink.h>
+    include <sys/ioctl.h>
+    include <unistd.h>
+
+In file included from ../git/src/6to4.c:34:0:
+/scratch/yocto/build-tgm-r3-poky-fpp-tgm.pyro/tmp/work/tgm_r3-poky-linux-musl/connman/1.33-git4+AUTOINC+aa5b3dc12b-r0/recipe-sysroot/usr/include/linux/if.h:97:2: error: expected identifier before numeric constant
+  IFF_LOWER_UP   = 1<<16, /* __volatile__ */
+  ^
+
+This is because at that time, IFF_LOWER_UP has been converted
+to 0x10000 already:
+enum net_device_flags {
+ 0x10000 = 1<<16,
+ 0x20000 = 1<<17,
+ 0x40000 = 1<<18,
+
+};
+
+Upstream-Status: Pending
+Signed-off-by: André Draszik <adraszik@tycoint.com>
+Acked-by: Stephane Ayotte <sayotte@tycoint.com>
+---
+ include/uapi/linux/libc-compat.h | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/include/uapi/linux/libc-compat.h b/include/uapi/linux/libc-compat.h
+index f11ec0e..2003ae4 100644
+--- a/include/uapi/linux/libc-compat.h
++++ b/include/uapi/linux/libc-compat.h
+@@ -70,7 +70,8 @@
+ #define __UAPI_DEF_IF_NET_DEVICE_FLAGS 0
+ /* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */
+ #ifndef __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO
+-#define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1
++/* musl has these defined */
++#define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 0
+ #endif /* __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO */
+ 
+ #else /* _NET_IF_H */
+-- 
+2.11.0
+
diff --git a/meta/recipes-kernel/linux-libc-headers/linux-libc-headers_4.10.bb b/meta/recipes-kernel/linux-libc-headers/linux-libc-headers_4.10.bb
index 108446aa34..29262789a8 100644
--- a/meta/recipes-kernel/linux-libc-headers/linux-libc-headers_4.10.bb
+++ b/meta/recipes-kernel/linux-libc-headers/linux-libc-headers_4.10.bb
@@ -4,6 +4,7 @@ SRC_URI_append_libc-musl = "\
     file://0001-libc-compat.h-fix-some-issues-arising-from-in6.h.patch \
     file://0002-libc-compat.h-prevent-redefinition-of-struct-ethhdr.patch \
     file://0003-remove-inclusion-of-sysinfo.h-in-kernel.h.patch \
+    file://0001-libc-compat.h-musl-_does_-define-IFF_LOWER_UP-DORMAN.patch \
    "
 
 SRC_URI[md5sum] = "b5e7f6b9b2fe1b6cc7bc56a3a0bfc090"
-- 
2.11.0