This is preparation for moving address environments out of the group
structure into the tcb.
Why move ? Because the group is destroyed very early in the exit phase,
but the MMU mappings are needed until the context switch to the next
process is complete. Otherwise the MMU will lose its mappings and the
system will crash.
When CONFIG_SYMTAB_ORDEREDBYNAME is selected most code will use
the ordered search function. When it is not selected no code will
use the ordered search function. This change merges the two
functions and varies its behaviour based on the config setting,
such that all callers can simply call the one search function
and get the best behaviour.
An additional configuration option allows leading underscores to
be stripped from symbols being relocated in loaded objects. This
allows toolchains which prefix C symbol with underscores to make
loadable ELF objects.
