same code works on windows, not on mac

[kjs]

This program:

{{{.sub main

a() b()

.end .sub a

say "a"

.end .sub b

say "b"

.end }}}

Works fine on windows, whereas on MacOS 10.6, I see:

$ ./pirc -b -x inv.pir a maximum recursion depth exceeded current instr.: 'b' pc 26 (inv.pir:11) called from Sub 'main' pc -1 ((unknown file):-1)

Not tested in Linux.