Merge commit 459e8e948 from llvm git (by Justin Hibbits):

Merge commit 459e8e948 from llvm git (by Justin Hibbits):

  [PowerPC]: Don't allow r0 as a target for LD_GOT_TPREL_L/32

  Summary:
  The linker is free to relax this (relocation R_PPC_GOT_TPREL16)
  against R_PPC_TLS, if it sees fit (initial exec to local exec). If r0
  is used, this can generate execution-invalid code (converts to 'addi
  %rX, %r0, FOO, which translates in PPC-lingo to li %rX, FOO). Forbid
  this instead.

  This fixes static binaries using locales on FreeBSD/powerpc (tested
  on FreeBSD/powerpcspe).

  Reviewed By: nemanjai
  Differential Revision: https://reviews.llvm.org/D76662

Requested by:	jhibbits
MFC after:	6 weeks
X-MFC-With:	358851