Add libuserdefs and use in cmd/{oamuser,passwd}

*** 88,98 ****
  $(USERDEL) :=   LIBS = $(LIBUSRGRP)
  
  $(USERMOD) :=   OBJS = $(MOD_OBJ)
  $(USERMOD) :=   LIBS = $(LIBUSRGRP)
  
! LDLIBS +=       -lbsm -lnsl -lsecdb -lproject -lzfs -ltsol
  
  .PARALLEL: $(OBJECTS)
  
  all:    $(PRODUCT)
  
--- 88,98 ----
  $(USERDEL) :=   LIBS = $(LIBUSRGRP)
  
  $(USERMOD) :=   OBJS = $(MOD_OBJ)
  $(USERMOD) :=   LIBS = $(LIBUSRGRP)
  
! LDLIBS +=       -luserdefs -lbsm -lnsl -lsecdb -lproject -lzfs -ltsol
  
  .PARALLEL: $(OBJECTS)
  
  all:    $(PRODUCT)