Compile wireguard on 19.07.10?

Hi to all
i want to reuse my old rb750 (plain 750) to make a WireGuard hub
yes, i know, it is old and slow
but i need this only for snmp/ssh purpose on WG peers, so total BW will be arround 1Mbps

i tried to compile stripped image from GIT, but when i enable WireGuard, compile stop with error

make[4]: Entering directory '/mnt/disk3/openwrt1907/build_dir/target-mips_24kc_musl/linux-ar71xx_mikrotik/linux-4.14.275'
  CC [M]  /mnt/disk3/openwrt1907/build_dir/target-mips_24kc_musl/linux-ar71xx_mikrotik/wireguard-linux-compat-1.0.20200611/src/main.o
In file included from <command-line>:0:0:
/mnt/disk3/openwrt1907/build_dir/target-mips_24kc_musl/linux-ar71xx_mikrotik/wireguard-linux-compat-1.0.20200611/src/compat/compat.h:1008:34: error: redefinition of 'icmpv6_send'
 #define __compat_icmpv6_ndo_send icmpv6_send
                                  ^
/mnt/disk3/openwrt1907/build_dir/target-mips_24kc_musl/linux-ar71xx_mikrotik/wireguard-linux-compat-1.0.20200611/src/compat/compat.h:1011:25: note: in expansion of macro '__compat_icmpv6_ndo_send'
 #define icmpv6_ndo_send __compat_icmpv6_ndo_send
                         ^~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/icmpv6.h:58:20: note: in expansion of macro 'icmpv6_ndo_send'
 static inline void icmpv6_ndo_send(struct sk_buff *skb_in, u8 type, u8 code, __u32 info)
                    ^~~~~~~~~~~~~~~
In file included from ./include/net/ndisc.h:50:0,
                 from ./include/net/ipv6.h:21,
                 from ./include/net/inetpeer.h:16,
                 from ./include/net/ip6_fib.h:23,
                 from ./include/net/dst_cache.h:8,
                 from /mnt/disk3/openwrt1907/build_dir/target-mips_24kc_musl/linux-ar71xx_mikrotik/wireguard-linux-compat-1.0.20200611/src/peer.h:17,
                 from /mnt/disk3/openwrt1907/build_dir/target-mips_24kc_musl/linux-ar71xx_mikrotik/wireguard-linux-compat-1.0.20200611/src/queueing.h:9,
                 from /mnt/disk3/openwrt1907/build_dir/target-mips_24kc_musl/linux-ar71xx_mikrotik/wireguard-linux-compat-1.0.20200611/src/main.c:9:
./include/linux/icmpv6.h:47:20: note: previous definition of 'icmpv6_send' was here
 static inline void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
                    ^~~~~~~~~~~
scripts/Makefile.build:329: recipe for target '/mnt/disk3/openwrt1907/build_dir/target-mips_24kc_musl/linux-ar71xx_mikrotik/wireguard-linux-compat-1.0.20200611/src/main.o' failed
make[5]: *** [/mnt/disk3/openwrt1907/build_dir/target-mips_24kc_musl/linux-ar71xx_mikrotik/wireguard-linux-compat-1.0.20200611/src/main.o] Error 1

build system is ubuntu 18.04