cmd/link: rationalize -s and -w flags with Mach-O external linking
Currently, on Mach-O in external linking mode, the handling of -s
and -w flags are a bit mixed: neither flag disables the symbol
table, and both flags disable DWARF.
This CL makes it do what is documented: -s disables symbol table,
and -w disables DWARF. For the Darwin system linker, the -s flag
(strip symbol table) is obsolete. So we strip it afterwards. We
already use the strip command to strip the debug STAB symbols if
we need to combine DWARF. With this CL we'll use an additional
flag to strip more symbols. And we now also use strip if -s is
specified and we don't need to combine DWARF.
Change-Id: I9bed24fd388f2bd5b0ffa4ec2db46a4a2f6b1016
Reviewed-on: https://go-review.googlesource.com/c/go/+/493136 Reviewed-by: Than McIntosh <thanm@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>