This patches LLVM to use ELFv2 on ppc64 unconditionally unless overridden. We
need this because unlike most distros we use ELFv2 for both glibc and musl
on big endian ppc64.

--- a/lib/Target/PowerPC/PPCTargetMachine.cpp
+++ b/lib/Target/PowerPC/PPCTargetMachine.cpp
@@ -214,9 +214,8 @@

   switch (TT.getArch()) {
   case Triple::ppc64le:
-    return PPCTargetMachine::PPC_ABI_ELFv2;
   case Triple::ppc64:
-    return PPCTargetMachine::PPC_ABI_ELFv1;
+    return PPCTargetMachine::PPC_ABI_ELFv2;
   default:
     return PPCTargetMachine::PPC_ABI_UNKNOWN;
   }
--- a/test/CodeGen/PowerPC/ppc64-elf-abi.ll
+++ b/test/CodeGen/PowerPC/ppc64-elf-abi.ll
@@ -1,4 +1,5 @@
-; RUN: llc -verify-machineinstrs -mtriple=powerpc64-unknown-linux-gnu < %s | FileCheck %s -check-prefix=CHECK-ELFv1
+; RUN: llc -verify-machineinstrs -mtriple=powerpc64-unknown-linux-gnu < %s | FileCheck %s -check-prefix=CHECK-ELFv2
+; RUN: llc -verify-machineinstrs -mtriple=powerpc64-unknown-linux-musl < %s | FileCheck %s -check-prefix=CHECK-ELFv2
 ; RUN: llc -verify-machineinstrs -mtriple=powerpc64-unknown-linux-gnu -target-abi elfv1 < %s | FileCheck %s -check-prefix=CHECK-ELFv1
 ; RUN: llc -verify-machineinstrs -mtriple=powerpc64-unknown-linux-gnu -target-abi elfv2 < %s | FileCheck %s -check-prefix=CHECK-ELFv2
 ; RUN: llc -verify-machineinstrs -mtriple=powerpc64le-unknown-linux-gnu < %s | FileCheck %s -check-prefix=CHECK-ELFv2