GNU linker ld usage question.

From: SYLee (dobest03_at_empal.com)
Date: 07/13/04 

Date: 12 Jul 2004 18:59:54 -0700

Hi..

Currently I've been looking into the Makefile of bootloader "DAS
U-Boot".
At final build stage, gnu linker links all object and produce
the u-boot by the following Makefile target rule:

u-boot: depend $(SUBDIRS) $(OBJS) $(LIBS) $(LDSCRIPT)
                UNDEF_SYM=`$(OBJDUMP) -x $(LIBS) | sed -n -e
's/.*\(__u_boot_cmd_.*\)/-u\1/p'|sort|uniq`;\
                $(LD) $(LDFLAGS) $$UNDEF_SYM $(OBJS) \
                        --start-group $(LIBS) $(PLATFORM_LIBS) --end-group \
                        -Map u-boot.map -o u-boot

$(LDFLAGS) variable ends "-n" and UNDEF_SYM is undefined symbol name
list.
Can the undefined symbol names be the non-option argument of gnu ld?
According to manual page or info, I haven't found any mention of it.

Do I misunderstand at some point about usage of ld?
If anyone have a answer please let me know.

Thanks.