The +objdebugcompile-line option is off by default. That is, +noobjdebug
is the default.
The +W option is off by default. That is, warnings are
enabled.
The +We option is off by default. That is, warnings are
not treated as errors.
The +Ww option is off by default. That is, only warnings
indicating that code generation might be affected are issued.
The +Oreusedir option is off by default. That is, intermediate
object files are not saved between links and are recompiled to object
files at every link.
The +Olevel=name option is off by default. That is, without this option,
all functions are compiled at the level specified by the -O option
or the ordinary +Olevel option.
The +O[no]promote_indirect_calls option is off by default. That is, +Onopromote_indirect_calls is the default.