Without the change build on upstream gcc-10 fails as:
ld: dfa.o:/build/gnugo-3.8/patterns/../engine/liberty.h:861: multiple definition of
`meaningless_white_moves'; mkpat.o:/build/gnugo-3.8/patterns/../engine/liberty.h:861: first defined here
ld: dfa.o:/build/gnugo-3.8/patterns/../engine/liberty.h:860: multiple definition of
`meaningless_black_moves'; mkpat.o:/build/gnugo-3.8/patterns/../engine/liberty.h:860: first defined here