Mass rename C1x references to C11. The name hasn't proliferated like "C++0x" so this patch is surprisingly small.

Also drop -Wc1x-extensions in favor of -Wc11-extensions. I don't think we need to keep this around for compatibility.

llvm-svn: 147221
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 61d1748..ad12e3d 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -270,7 +270,7 @@
     // FIXME: C1x doesn't have a defined version number yet, so pick something
     // that is the minimum possible according to their placeholder scheme
     // 201ymmL.
-    if (LangOpts.C1X)
+    if (LangOpts.C11)
       Builder.defineMacro("__STDC_VERSION__", "201001L");
     else if (LangOpts.C99)
       Builder.defineMacro("__STDC_VERSION__", "199901L");