It means to keep friendship or make friends. Phrases like this include making friends, keeping friendship and so on. But usually a with, makefriendswith is added after it, which means making friends with something. The sentence with complete meaning is more full and full of emotion.
In this phrase, make is a verb, meaning to make, assemble, write, produce, make and make a bed. Friends is a plural noun, which means to have friends, sponsors, supporters, own people, comrades and allies.