What is the meaning of the title "Far Cry from Africa?"

The poem's title references the history of imperialism and colonization of Africa by other countries, particularly the British. 

"Between this Africa and the English tongue I love?
Betray them both, or give back what they give?
How can I face such slaughter and be cool? How
can I turn from Africa and live?" (Walcott)

The poet speaks of the struggle between the white forces that rule Africa in this period and the uprising in the communities that attempted to free themselves from British domination. 

"It is likely that Walcott's West Indian origins, linked back to part of his family's original homeland in Africa, and the domination of both his country and Kenya by Britain spurred him to take special note of events in Kenya"

That is why he wrote the poem, to chronicle the events occurring in Kenya, which were similar to those happening in other British colonies, which suggest that the cry for freedom from these nations echoed through and beyond the continent of Africa.  

A shared struggle that deeply affected the poet who has both black and white ancestry.