Dwarf: support for LTO where a single object file can have multiple line tables

We generate one line table for each compilation unit in the object file.
Reviewed by Eric and Kevin.

rdar://problem/13067005


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174445 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCContext.cpp b/lib/MC/MCContext.cpp
index aa52b49..a074003 100644
--- a/lib/MC/MCContext.cpp
+++ b/lib/MC/MCContext.cpp
@@ -40,7 +40,7 @@
   CompilationDir(llvm::sys::Path::GetCurrentDirectory().str()),
   CurrentDwarfLoc(0,0,0,DWARF2_FLAG_IS_STMT,0,0), 
   DwarfLocSeen(false), GenDwarfForAssembly(false), GenDwarfFileNumber(0),
-  AllowTemporaryLabels(true), AutoReset(DoAutoReset) {
+  AllowTemporaryLabels(true), DwarfCompileUnitID(0), AutoReset(DoAutoReset) {
 
   MachOUniquingMap = 0;
   ELFUniquingMap = 0;