iproute2: honor COPTS; add missing include

CFLAGS has been passed 2 times, one from TARGET_CFLAGS in EXTRA_CCOPTS,
the other from Makefile in PKG_BUILD_DIR.

Fix this issue by adjusting flags' order and remove duplicated flags

package/network/utils/iproute2/Makefile

@@ -20,6 +20,7 @@ PKG_LICENSE:=GPL-2.0
 PKG_BUILD_DIR:=$(BUILD_DIR)/$(PKG_NAME)-$(BUILD_VARIANT)/$(PKG_NAME)-$(PKG_VERSION)
 
 include $(INCLUDE_DIR)/package.mk
+include $(INCLUDE_DIR)/kernel.mk
 
 define Package/iproute2/Default
   TITLE:=Routing control utility ($(2))
@@ -83,7 +84,7 @@ TARGET_CFLAGS += -DHAVE_SETNS
 TARGET_CFLAGS += -ffunction-sections -fdata-sections
 
 MAKE_FLAGS += \
-	EXTRA_CCOPTS="$(TARGET_CFLAGS) -I../include -I$(STAGING_DIR)/usr/include/libnl-tiny" \
+	EXTRA_CCOPTS="-I$(STAGING_DIR)/usr/include/libnl-tiny" \
 	KERNEL_INCLUDE="$(LINUX_DIR)/include" \
 	SHARED_LIBS="" \
 	LDFLAGS="$(TARGET_LDFLAGS) -Wl,--gc-sections" \

package/network/utils/iproute2/patches/999-honor-copts.patch

@@ -0,0 +1,11 @@
+--- a/Makefile
++++ b/Makefile
+@@ -38,7 +38,7 @@ CCOPTS = -O2 $(EXTRA_CCOPTS)
+ WFLAGS := -Wall -Wstrict-prototypes  -Wmissing-prototypes
+ WFLAGS += -Wmissing-declarations -Wold-style-definition -Wformat=2
+
+-CFLAGS := $(WFLAGS) $(CCOPTS) -I../include $(DEFINES) $(CFLAGS)
++CFLAGS := $(WFLAGS) -I../include $(EXTRA_CCOPTS) $(DEFINES) $(CFLAGS)
+ YACCFLAGS = -d -t -v
+
+ SUBDIRS=lib ip tc bridge misc genl tipc man