Remove VISIBILITY_HIDDEN from class/struct found inside anonymous namespaces.
Chris claims we should never have visibility_hidden inside any .cpp file but
that's still not true even after this commit.

llvm-svn: 85042
diff --git a/llvm/lib/Transforms/IPO/MergeFunctions.cpp b/llvm/lib/Transforms/IPO/MergeFunctions.cpp
index 13bbf9c..c3433c7 100644
--- a/llvm/lib/Transforms/IPO/MergeFunctions.cpp
+++ b/llvm/lib/Transforms/IPO/MergeFunctions.cpp
@@ -62,7 +62,7 @@
 STATISTIC(NumFunctionsMerged, "Number of functions merged");
 
 namespace {
-  struct VISIBILITY_HIDDEN MergeFunctions : public ModulePass {
+  struct MergeFunctions : public ModulePass {
     static char ID; // Pass identification, replacement for typeid
     MergeFunctions() : ModulePass(&ID) {}