Emit uuid globals as linkonce_odr

Patch by Nico Rieck!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189860 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 1eb5a09..3b28d9d 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -1052,7 +1052,7 @@
 
   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
       getModule(), Init->getType(),
-      /*isConstant=*/true, llvm::GlobalValue::ExternalLinkage, Init, Name);
+      /*isConstant=*/true, llvm::GlobalValue::LinkOnceODRLinkage, Init, Name);
   return GV;
 }