In order to support Mach-O better, add support for subsections, as
used by Mach-O "subsections_via_symbols". We also want to add
infrastructure to support this by downcalling to the backend to
indicate if a new subsection is needed.
Currently this supports a maximum of 2^14 subsections per section for
Mach-O; this can be addressed by adding a level of indirection (or
cleaning up the handling of sections so we have an actual data
structure.)
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
98578071b9