Disable building fdisk on m68k

--- fdisk/Makefile
+++ fdisk/Makefile
@@ -18,8 +18,10 @@
 endif
 endif
 
+ifneq "$(ARCH)" "m68k"
 SBIN:=$(SBIN) fdisk
 MAN8:=$(MAN8) fdisk.8
+endif
 
 ifneq "$(ARCH)" "sparc"
 SBIN:=$(SBIN) $(CFDISK) sfdisk