[CodeView, PDB] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC).

llvm-svn: 306911
diff --git a/llvm/lib/DebugInfo/CodeView/SymbolSerializer.cpp b/llvm/lib/DebugInfo/CodeView/SymbolSerializer.cpp
index 9f2d619..9a2e776 100644
--- a/llvm/lib/DebugInfo/CodeView/SymbolSerializer.cpp
+++ b/llvm/lib/DebugInfo/CodeView/SymbolSerializer.cpp
@@ -1,4 +1,4 @@
-//===- SymbolSerializer.cpp -------------------------------------*- C++ -*-===//
+//===- SymbolSerializer.cpp -----------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -8,6 +8,13 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/DebugInfo/CodeView/SymbolSerializer.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/DebugInfo/CodeView/SymbolRecord.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/Error.h"
+#include <cassert>
+#include <cstdint>
+#include <cstring>
 
 using namespace llvm;
 using namespace llvm::codeview;
@@ -15,7 +22,7 @@
 SymbolSerializer::SymbolSerializer(BumpPtrAllocator &Allocator,
                                    CodeViewContainer Container)
     : Storage(Allocator), RecordBuffer(MaxRecordLength),
-      Stream(RecordBuffer, llvm::support::little), Writer(Stream),
+      Stream(RecordBuffer, support::little), Writer(Stream),
       Mapping(Writer, Container) {}
 
 Error SymbolSerializer::visitSymbolBegin(CVSymbol &Record) {