Exit the command line into <built-in> instead of going directly from the command line to the input file.

We passed <built-in> on the way in, so we should pass it again on the way out.

llvm-svn: 90250
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 972c21f..cf6c561 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -523,6 +523,11 @@
       AddImplicitInclude(PredefineBuffer, Path);
   }
 
+  // Exit the command line and go back to <built-in> (2 is LC_LEAVE).
+  LineDirective = "# 1 \"<built-in>\" 2\n";
+  PredefineBuffer.insert(PredefineBuffer.end(),
+                         LineDirective, LineDirective+strlen(LineDirective));
+
   // Null terminate PredefinedBuffer and add it.
   PredefineBuffer.push_back(0);
   PP.setPredefines(&PredefineBuffer[0]);