Create conspage.h to declare functions defined in conspage.c

Update files that depend on conspage functions to include conspage.h
Declare as static all functions in conspage.c that are not needed externally.
Add dependencies to makefile.

	modified:   bin/makefile-darwin.386-x
	modified:   bin/makefile-tail
	new file:   inc/conspage.h
	modified:   src/conspage.c
	modified:   src/mvs.c
	modified:   src/rplcons.c
	modified:   src/xc.c
	modified:   src/z2.c

inc/conspage.h

@@ -0,0 +1,3 @@
+struct conspage *next_conspage(void);
+LispPTR N_OP_cons(register int cons_car, register int cons_cdr);
+LispPTR cons(LispPTR cons_car, LispPTR cons_cdr);