Add clang-cc option "-analyzer-experimental-checks" to enable experimental path-sensitive checks.  The idea is to separate "barely working" or "skunkworks" checks from ones that should always run.  Later we need more fine-grain checker control.

llvm-svn: 87053
diff --git a/clang/lib/Frontend/AnalysisConsumer.cpp b/clang/lib/Frontend/AnalysisConsumer.cpp
index d51730c..e8bd920 100644
--- a/clang/lib/Frontend/AnalysisConsumer.cpp
+++ b/clang/lib/Frontend/AnalysisConsumer.cpp
@@ -332,7 +332,9 @@
   Eng.RegisterInternalChecks(); // FIXME: Internal checks should just
                                 // automatically register.
   RegisterAppleChecks(Eng, *D);
-
+  
+  if (C.Opts.EnableExperimentalChecks)
+    RegisterExperimentalChecks(Eng);
 
   // Set the graph auditor.
   llvm::OwningPtr<ExplodedNode::Auditor> Auditor;