cbfstool: add ELF symbol, relocation, and string table support

In order to convert rmodules back into ELF files one needs
to add in the relocations so they can be converted back to
rmodules. Because of that requirement symbol tables need
to be present because the relocations reference the symbols.
Additionally, symbol tables reference a string table for the
symbol names. Provide the necessary support for adding all
of those things to an ELF writer.

TEST=Extracted rmodule from a cbfs and compared with the
     source ELF file. Confirmed relocations and code sizes
     are correct.

Change-Id: I07e87a30b3371ddedabcfc682046e3db8c956ff2
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/12221
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
2 files changed