Drop the hidden visibility from DebugHandlerBase for now.

If a class has hidden visibility all derived classes and all classes
that have it as a member must have hidden visibility too. That may
be fixable here but requires changes to quite a lot of debug info
classes.

This is also one of the things that GCC enforces aggressively while
clang ignores it, making testing more annoying than necessary.

llvm-svn: 260529

llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.h

@@ -26,7 +26,7 @@ class MachineModuleInfo;
 
 /// Base class for debug information backends. Common functionality related to
 /// tracking which variables and scopes are alive at a given PC live here.
-class LLVM_LIBRARY_VISIBILITY DebugHandlerBase : public AsmPrinterHandler {
+class DebugHandlerBase : public AsmPrinterHandler {
 protected:
   DebugHandlerBase(AsmPrinter *A);