Implement the MachO do_dead_strip directive, which sets a flag on the
corresponding section. This as well as subsections_by_symbols are
reimplemented as pragmas; if someone uses the predefined macro they
still get the expected behavior.
However, this allows someone to write:
%pragma macho subsections_by_symbols
... and have it ignored if compiling for, say, ELF.
Also, implement the following section attributes:
zerofill, no_dead_strip, live_support, strip_static_syms
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
9f16cfde4c