don't compress files in ZONE/*, they are not opened using bopen().
you may compress the INFO files, the action file, and the datafiles
generated by mkdata.c/generate.c.

if you refuse to use bopen, it is equivalent to:

	#define bopen(F)  fopen(F,"r")
	#define bclose(F) fclose(F)

on normal files, and to:

	#define bopen(F)  popen(f,"r")
	#define bclose(F) pclose(F)

on pipes. bopen/bclose will use stat to know if it is working on a
pipe or on a file.

-val