Changes, made by Edzer Pebesma:

added this file
removed all files z* (not used), except for zmatrix.h and zmatrix2.h

MACHINES/Linux/machine.h:
	removed (uncommented) #define COMPLEX 1
	added #include <math.h>

makefile.in
	renamed target `sparse' to `with-sparse' (gnu make tries to build
	a program sparse from sparse.o if this is not done)

MACHINES/RS6000/machine.h:
	removed (uncommented) #define COMPLEX 1
	added #include <math.h>
MACHINES/RS6000/makefile:
	remove -O
	target sparse --> with-sparse
