(enable_break): For SVR4 systems, first try to use the debugger
interfaces in the dynamic linker to track shared library events
as they happen, then fall back to BKPT_AT_SYMBOL code. Convert
BKPT_AT_SYMBOL code to use shared library event breakpoints.
(solib_create_inferior_hook): Simplify BKPT_AT_SYMBOL code,
it no longer needs to restart/wait on the inferior.
* symfile.c (find_lowest_section): No longer static.
* symfile.h (find_lowest_section): Corresponding changes.
Wraps up 7763 work, simplifies BKPT_AT_SYMBOL code somewhat, and allows
debugging of startup code.
464c6c5f3f