This change adds support to the rtems-syms code to generate a suitable
ELF object you can link to the base image kernel in the embed mode or
you can load with the run-time load mode.
The change fixes a bug in the framework where local ELF symbols
were being placed in the external symbol table. The external
symbol table has been removed and a global, weak and local set
of tables is now provided as this is more aligned with the ELF
format.
