patches/routing/cjdns: Fix compiling cjdns on gcc8

Added condition to remove -Wno_overread warning if toolchain is lower than version 11, based on recommendation (https://github.com/NixOS/nixpkgs/pull/168997) Added two patches from openwrt stream. patch3.10 (1df5290b92625823bb9725a5406383116463f3ac) invalid-pointer (d710a7938977c84d6ea0f74b21dc50111e5e968c) In previous patch there was error with empty intcmp. This commit fix error in in 26c38a17 Rename TARGET_CCFLAGS to EXTRA_TARGET_CFLAGS, because TARGET_CCFLAGS is for C++ stuff.