win: Add a note about /Z7 obsolescence regarding CodeView debug info

compat/non_win/dbghelp.h

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 546 matching lines @@
   //! <a
   //! href="http://pierrelib.pagesperso-orange.fr/exec_formats/MS_Symbol_Type_v1.0.pdf#page=71">Microsoft
   //! Symbol and Type Information</a>, section 7.2, “Debug Information Format”
   //! for a list of debug information formats, and <a
   //! href="http://undocumented.rawol.com/sbs-w2k-1-windows-2000-debugging-support.pdf#page=63">Undocumented
   //! Windows 2000 Secrets</a>, Windows 2000 Debugging Support/Microsoft Symbol
   //! File Internals/CodeView Subsections for an in-depth description of the
   //! CodeView 4.1 format. Signatures seen in the wild include “NB09”
   //! (0x3930424e) for CodeView 4.1 and “NB11” (0x3131424e) for CodeView 5.0.
   //! This form of debugging information within the module, as opposed to a link
-  //! to an external `.pdb` file, is chosen by building with `/Z7`.
+  //! to an external `.pdb` file, is chosen by building with `/Z7` in Visual
+  //! Studio 6.0 (1998) and earlier. This embedded form of debugging information
+  //! is now considered obsolete.
   //!
   //! On Windows, the CodeView record is taken from a module’s
   //! IMAGE_DEBUG_DIRECTORY entry whose Type field has the value
   //! IMAGE_DEBUG_TYPE_CODEVIEW (`2`), if any. Records in
   //! crashpad::CodeViewRecordPDB70 format are generated by Visual Studio .NET
   //! (2002) (version 7.0) and later.
   //!
   //! When the CodeView record is not present, the fields of this
   //! MINIDUMP_LOCATION_DESCRIPTOR will be `0`.
   MINIDUMP_LOCATION_DESCRIPTOR CvRecord;
@@ skipping 396 matching lines @@
   //!  - A MINIDUMP_MODULE_LIST stream. All loaded modules are present.
   //!  - Typically, a MINIDUMP_MEMORY_LIST stream containing duplicate pointers
   //!    to the stack memory regions also referenced by the MINIDUMP_THREAD_LIST
   //!    stream. This type of minidump file also includes a
   //!    MINIDUMP_MEMORY_DESCRIPTOR containing the 256 bytes centered around
   //!    the exception address or the instruction pointer.
   MiniDumpNormal = 0x00000000,
 };
 
 #endif  // CRASHPAD_COMPAT_NON_WIN_DBGHELP_H_