Fix memneq workaround

Makefile

@@ -38,8 +38,7 @@ $(WIREGUARD_TAR):
 # use memneq implementation as it doesn't appear to be included on the D218j.
 $(WIREGUARD_DIR)/src/Makefile: $(WIREGUARD_TAR)
 	tar -xf $(WIREGUARD_TAR)
-	echo 'ccflags-y += -include $(kbuild-dir)/compat/memneq/include.h' >> $(WIREGUARD_DIR)/src/compat/Kbuild.include
-	echo 'wireguard-y += compat/memneq/memneq.o' >> $(WIREGUARD_DIR)/src/compat/Kbuild.include
+	patch $(WIREGUARD_DIR)/src/compat/Kbuild.include $(ROOT_DIR)/memneq.patch
 
 # Build the wg command line tool
 $(WG_TARGET): $(LIBMNL_DIR)/src/.libs/libmnl.a $(WIREGUARD_DIR)/src/Makefile

memneq.patch

@@ -0,0 +1,13 @@
+--- Kbuild.include	2019-03-17 16:02:33.388208274 +0000
++++ Kbuild.include	2019-03-17 16:02:45.951895692 +0000
+@@ -42,10 +42,8 @@
+ wireguard-y += compat/udp_tunnel/udp_tunnel.o
+ endif
+
+-ifeq ($(shell grep -s -F "int crypto_memneq" "$(srctree)/include/crypto/algapi.h"),)
+ ccflags-y += -include $(kbuild-dir)/compat/memneq/include.h
+ wireguard-y += compat/memneq/memneq.o
+-endif
+
+ ifeq ($(wildcard $(srctree)/arch/arm/include/asm/neon.h)$(CONFIG_ARM),y)
+ ccflags-y += -I$(src)/compat/neon-arm/include