lib: move compat links from targetdirs to proper makefiles

*** 30,39 ****
--- 30,40 ----
  BLTOBJ=         msg.o
  
  OBJECTS =       $(BLTOBJ) $(COMOBJS) $(COMOBJS64) $(PLTOBJS)
  
  include         $(SRC)/lib/Makefile.lib
+ include         $(SRC)/lib/Makefile.rootfs
  include         $(SRC)/cmd/sgs/Makefile.com
  
  SRCDIR =        ../common
  
  CPPFLAGS +=     -I$(SRCBASE)/lib/libc/inc