[Darwin, machopic 4/n] Arrange to indirect IVARs when needed.

[Darwin, machopic 4/n] Arrange to indirect IVARs when needed.

Objective C V2 (m64) IVAR offset refs from Apple GCC-4.x have an indirection
for m64 code on PPC (which is the only 64b user for Mach-O PIC).  Apple GCC
4.x places the indirections in the .data section, however this seems to have
been unintentional - and we are placing the indirections in the non-lazy
symbol pointers section.

gcc/ChangeLog:

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

	* config/darwin.c: Lookup Objective C metadata and force indirection
	for IVAR refs.

From-SVN: r276848