make sure #pragma clang is treated the same way as #pragma gcc in -E mode,
unknown pragmas should just be passed through to the .i file.

llvm-svn: 118659
diff --git a/clang/lib/Frontend/PrintPreprocessedOutput.cpp b/clang/lib/Frontend/PrintPreprocessedOutput.cpp
index 00ab3c3..6019b30 100644
--- a/clang/lib/Frontend/PrintPreprocessedOutput.cpp
+++ b/clang/lib/Frontend/PrintPreprocessedOutput.cpp
@@ -579,8 +579,9 @@
       new PrintPPOutputPPCallbacks(PP, *OS, !Opts.ShowLineMarkers,
                                    Opts.ShowMacros, Opts.ShowHeaderIncludes);
   PP.AddPragmaHandler(new UnknownPragmaHandler("#pragma", Callbacks));
-  PP.AddPragmaHandler("GCC", new UnknownPragmaHandler("#pragma GCC",
-                                                      Callbacks));
+  PP.AddPragmaHandler("GCC", new UnknownPragmaHandler("#pragma GCC",Callbacks));
+  PP.AddPragmaHandler("clang",
+                      new UnknownPragmaHandler("#pragma clang", Callbacks));
 
   PP.addPPCallbacks(Callbacks);