Make TargetInfo store an actual DataLayout instead of a string.

Use it to calculate UserLabelPrefix, instead of specifying it (often
incorrectly).

Note that the *actual* user label prefix has always come from the
DataLayout, and is handled within LLVM. The main thing clang's
TargetInfo::UserLabelPrefix did was to set the #define value. Having
these be different from each-other is just silly.

Differential Revision: http://reviews.llvm.org/D17183

llvm-svn: 262737
diff --git a/clang/unittests/Lex/PPConditionalDirectiveRecordTest.cpp b/clang/unittests/Lex/PPConditionalDirectiveRecordTest.cpp
index 9345fc2..bceeac5 100644
--- a/clang/unittests/Lex/PPConditionalDirectiveRecordTest.cpp
+++ b/clang/unittests/Lex/PPConditionalDirectiveRecordTest.cpp
@@ -22,7 +22,6 @@
 #include "clang/Lex/PreprocessorOptions.h"
 #include "gtest/gtest.h"
 
-using namespace llvm;
 using namespace clang;
 
 namespace {
@@ -89,7 +88,8 @@
       "#endif\n"
       "9\n";
 
-  std::unique_ptr<MemoryBuffer> Buf = MemoryBuffer::getMemBuffer(source);
+  std::unique_ptr<llvm::MemoryBuffer> Buf =
+      llvm::MemoryBuffer::getMemBuffer(source);
   SourceMgr.setMainFileID(SourceMgr.createFileID(std::move(Buf)));
 
   VoidModuleLoader ModLoader;