package/wavemon: fix kernel header collision

Fix the following build failure raised since bump to version 0.9.4 in
commit 5cae1a0d675eca41125b6430157d3d0d78d1220c:

In file included from iw_if.h:26:0,
                 from conf.c:19:
/home/buildroot/autobuild/instance-1/output-1/host/mips-buildroot-linux-gnu/sysroot/usr/include/linux/if.h:71:2: error: redeclaration of enumerator 'IFF_UP'
  IFF_UP    = 1<<0,  /* sysfs */
  ^
/home/buildroot/autobuild/instance-1/output-1/host/mips-buildroot-linux-gnu/sysroot/usr/include/net/if.h:44:5: note: previous definition of 'IFF_UP' was here
     IFF_UP = 0x1,  /* Interface is up.  */
     ^

Fixes:
 - http://autobuild.buildroot.org/results/cbdf3e0cf0bee8f1b076581768c24155afc320d9

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 57a1ce00a2c9f4b4b988f41b15ad01c6abc2a99c)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/wavemon/0001-iw_if.h-don-t-include-linux-if.h.patch

@@ -0,0 +1,41 @@
+From 4ac1482bb40376e47805c3737dfed60abb1dd3b4 Mon Sep 17 00:00:00 2001
+From: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+Date: Wed, 22 Dec 2021 00:39:35 +0100
+Subject: [PATCH] iw_if.h: don't include linux/if.h (#109)
+
+Don't include linux/if.h to avoid the following build failure:
+
+In file included from iw_if.h:31:0,
+                 from conf.c:19:
+/home/buildroot/autobuild/instance-3/output-1/host/arm-buildroot-linux-gnueabi/sysroot/usr/include/linux/if.h: At top level:
+/home/buildroot/autobuild/instance-3/output-1/host/arm-buildroot-linux-gnueabi/sysroot/usr/include/linux/if.h:143:8: error: redefinition of 'struct ifmap'
+ struct ifmap {
+        ^
+In file included from iw_if.h:26:0,
+                 from conf.c:19:
+/home/buildroot/autobuild/instance-3/output-1/host/arm-buildroot-linux-gnueabi/sysroot/usr/include/net/if.h:111:8: note: originally defined here
+ struct ifmap
+        ^
+
+Fixes:
+ - http://autobuild.buildroot.org/results/a6ee162cf04b70b144b54e1ca4b7b2421071c50c
+
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+[Retrieved from:
+https://github.com/uoaerg/wavemon/commit/4ac1482bb40376e47805c3737dfed60abb1dd3b4]
+---
+ iw_if.h | 1 -
+ 1 file changed, 1 deletion(-)
+
+diff --git a/iw_if.h b/iw_if.h
+index 9e7fa89..6607e0b 100644
+--- a/iw_if.h
++++ b/iw_if.h
+@@ -28,7 +28,6 @@
+ #include <net/ethernet.h>
+ #include <sys/types.h>
+ #include <sys/socket.h>
+-#include <linux/if.h>
+ 
+ /* Definitions from linux/ieee80211.h (not necessarily part of distro headers) */
+ #define WLAN_CAPABILITY_ESS		(1<<0)