macos: Fix GOT access to local defined symbols
macos: Fix GOT access to local defined symbols

if a GOT slot is required (due to codegen, indicated by
presence of some relocation types), then it needs to contain
the address of the wanted symbol, also when it's local and defined,
i.e. not overridable.  For simplicity we use a GOT slot for that as
well (other storage would require rewriting relocs and symbols,
as resolving of GOT relocs is hardwired to be based on s1->got).
But that means we need to fill in its indirect symbol mapping slot as
well, for which Mach-O provides a mean to say "not symbol based,
resolved locally".  So this fixes this testcase:

static int loc;
int _start(void)
{
  loc = 42;
  return loc - 42;
}

(where our codegen currently uses a GOT-based access for the write
by accident)

mingodad/tinycc,mingodad/tinycc,mingodad/tinycc,mirror/tinycc,mirror/tinycc,mirror/tinycc,mirror/tinycc,mingodad/tinycc