Revert "Give internal classes hidden visibility."

It works with clang, but GCC has different rules so we can't make all of those
hidden. This reverts commit r190534.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190536 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfAccelTable.h b/lib/CodeGen/AsmPrinter/DwarfAccelTable.h
index 1ea0bfb..7627313 100644
--- a/lib/CodeGen/AsmPrinter/DwarfAccelTable.h
+++ b/lib/CodeGen/AsmPrinter/DwarfAccelTable.h
@@ -65,7 +65,7 @@
 class DIE;
 class DwarfUnits;
 
-class LLVM_LIBRARY_VISIBILITY DwarfAccelTable {
+class DwarfAccelTable {
 
   static uint32_t HashDJB(StringRef Str) {
     uint32_t h = 5381;