[Darwin, machopic] Fix for 67183

[Darwin, machopic] Fix for 67183

When we're using the LLVM-based assembler (the default on modern Darwin)
the ordering of stubs and non-lazy symbol pointers is important.

Interleaving the output (current GCC behaviour) leads to crashes which
prevents us from building code with symbol stubs.

To resolve this, we order the output of stubs and symbol indirections:

1. Any indirections in the data section
2. Symbol stubs.
3. Non-lazy symbol pointers.

At present, we still emit LTO sections after these.

2019-10-27  Iain Sandoe  <iain@sandoe.co.uk>

	Backport from mainline
	2019-10-12  Iain Sandoe  <iain@sandoe.co.uk>

	PR target/67183
	* config/darwin.c (machopic_indirection): New field to flag
	non-lazy-symbol-pointers in the data section.
	(machopic_indirection_name): Compute if an indirection should
	appear in the data section.
	(machopic_output_data_section_indirection): New callback split
	from machopic_output_indirection.
	(machopic_output_stub_indirection): Likewise.
	(machopic_output_indirection): Retain the code for non-lazy
	symbol pointers in their regular section.
	(machopic_finish): Use the new callbacks to order the indirection
	output.

From-SVN: r277494