Revert "Revert "Upgrade to 5.0.71.48"" DO NOT MERGE

This reverts commit f2e3994fa5148cc3d9946666f0b0596290192b0e,
and updates the x64 makefile properly so it doesn't break that
build.

FPIIM-449

Change-Id: Ib83e35bfbae6af627451c926a9650ec57c045605
(cherry picked from commit 109988c7ccb6f3fd1a58574fa3dfb88beaef6632)
diff --git a/src/debug/x87/debug-x87.cc b/src/debug/x87/debug-x87.cc
index 8c04e02..8ddb82f 100644
--- a/src/debug/x87/debug-x87.cc
+++ b/src/debug/x87/debug-x87.cc
@@ -50,6 +50,9 @@
   DCHECK_EQ(kSize, patcher.masm()->SizeOfCodeGeneratedSince(&check_codesize));
 }
 
+bool DebugCodegen::DebugBreakSlotIsPatched(Address pc) {
+  return !Assembler::IsNop(pc);
+}
 
 void DebugCodegen::GenerateDebugBreakStub(MacroAssembler* masm,
                                           DebugBreakCallHelperMode mode) {