when you compiled this on plan 9, you must have 
either replaced stdlib.h with something else or have used
ape.  i substituted libbio and get almost the same performance
you did on linux.  i used my home cpu server, a amd64 revF 3800+.

	cpu% 8c -FVw t.c
	warning: t.c:64 set and not used: t
	cpu% 8l -o t t.8
	cpu% time t >/tmp/xyzw
	2.08u 0.05s 2.36r 	 t

i think the reason for the difference in performance is that somehow
your translation of print was calling write(2) for each integer printed.

assuming i understand the point of this program -- sorting a bunch of
integers, i rewrote this program using an array and qsort, which should
be more memory efficient and faster.  here's what i get

	cpu% time ./u >/tmp/xyz 
	0.08u 0.01s 0.22r 	 ./u

- erik