sb: Add options log_info.

Provide a log_info method for the options class to log the command line
and the python version string.
sb: Output the new info message.

With the set builder add nesting count support.
sb: Fix nesting if statements.

Nesting if statements did not correctly process the contents of
the nested if script. This change makes the processing uniform
across all the logic stages.
config: Update RTEMS to gdb-7.6.1.