PATCH: objcopy.c: redefine-sym-specific for archive files

[Daniel Marques]

If an archive file (e.g. libc.a) consists of more than one object file 
(e.g, a.o & b.o) each containing a definition for a symbol named 'foo', 
objcopy --redefine-sym foo=bar libc.a will redefine both symbols.

Example 1:

	[marques@c3linux objectdumps]$ nm libc.a

	a.o:
	00000000 b foo

	b.o:
	00000000 b foo

	[marques@c3linux objectdumps]$ objcopy --redefine-sym foo=bar libc.a

	[marques@c3linux objectdumps]$ nm libc.a

	a.o:
	00000000 b bar

	b.o:
	00000000 b bar


This might not always be the desired behavior.  The attached patch adds 
the --redefine-sym-specific option to object copy.  Its usage is

--redefine-sym-specific <objectfile>:<old>=<new>
               Redefine symbol name <old> to <new>, only for
                 specific <objectfile> component of input archive file


This flag allows the user to specify that the redefinition should only 
affect the symbol in the specified 'component' (object file) of the archive.



Example 2:

	[marques@c3linux objectdumps]$ nm libc.a

	a.o:
	00000000 b foo

	b.o:
	00000000 b foo

	[marques@c3linux objectdumps]$ objcopy --redefine-sym-specific 
a.o:foo=bar libc.a

	[marques@c3linux objectdumps]$ nm libc.a
	
	a.o:
	00000000 b bar

	b.o:
	00000000 b foo


Notice that a specify redefine will always override a general override 
for the same symbol name


Example 3:

	[marques@c3linux objectdumps]$ nm libc.a

	a.o:
	00000000 b foo

	b.o:
	00000000 b foo

	[marques@c3linux objectdumps]$ objcopy --redefine-sym foo=gnu 
--redefine-sym-specific a.o:foo=bar libc.a

	[marques@c3linux objectdumps]$ nm libc.a

	a.o:
	00000000 b bar

	b.o:
	00000000 b gnu


I did not include a version for reading these from a file, as that would 
require either 'generalizing' add_redefine_syms_file() or 'cloning' that 
function, and I though such a decision should be left to the maintainers.


Thanks.

Dan

P.S. Please cc me on reply, as I am not a subscriber to this list.

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