Green’s Dictionary of Slang

(US) one who perseveres in the face of challenges; a survivor.

1979		(con. c.1970) G. Hasford Short Timers (1985) 5: My orders are to weed out all the nonhackers who do not pack the gear to serve in my beloved Corps.
1990		(con. c.1970) G. Hasford Phantom Blooper 35: I check the slit trenches for non-hackers, juice freaks, and heads.