Initialize CompactUnwindSection so that other targets won't use an uninitialized value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138752 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCObjectFileInfo.cpp b/lib/MC/MCObjectFileInfo.cpp
index 0cf98bd..22da78e 100644
--- a/lib/MC/MCObjectFileInfo.cpp
+++ b/lib/MC/MCObjectFileInfo.cpp
@@ -505,7 +505,8 @@
   PersonalityEncoding = LSDAEncoding = FDEEncoding = FDECFIEncoding =
     TTypeEncoding = dwarf::DW_EH_PE_absptr;
 
-  EHFrameSection = 0; // Created on demand.
+  EHFrameSection = 0;           // Created on demand.
+  CompactUnwindSection = 0;     // Used only be select targets.
 
   Triple T(TT);
   Triple::ArchType Arch = T.getArch();