RFR: 8342869: Errors related to unused code on Windows after 8339120 in awt [v2]

[Julian Waters]

> After 8339120, gcc began catching many different instances of unused code in the Windows specific codebase. Some of these seem to be bugs. I've taken the effort to mark out all the relevant globals and locals that trigger the unused warnings and addressed all of them by commenting out the code as appropriate. I am confident that in many cases this simplistic approach of commenting out code does not fix the underlying issue, and the warning actually found a bug that should be fixed. In these instances, I will be aiming to fix these bugs with help from reviewers, so I recommend anyone reviewing who knows more about the code than I do to see whether there is indeed a bug that needs fixing in a different way than what I did
> 
> build.log on release configuration:
> 
> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/java.desktop/windows/native/libawt/windows/awt_Component.cpp:3560:39: warning: '_VKS_ALT_MASK' defined but not used [-Wunused-const-variable=]
>  3560 |                     static const UINT _VKS_ALT_MASK = 0x04;
>       |                                       ^~~~~~~~~~~~~
> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/java.desktop/windows/native/libawt/windows/awt_Font.cpp: In member function 'void CSegTable::MakeTable()':
> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/java.desktop/windows/native/libawt/windows/awt_Font.cpp:1361:14: warning: typedef 'PSUBTABLE' locally defined but not used [-Wunused-local-typedefs]
>  1361 | } SUBTABLE, *PSUBTABLE;
>       |              ^~~~~~~~~
> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/java.desktop/windows/native/libawt/windows/awt_Font.cpp: In member function 'virtual void CEUDCSegTable::Create(LPCWSTR)':
> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/java.desktop/windows/native/libawt/windows/awt_Font.cpp:1588:10: warning: typedef 'PHEAD' locally defined but not used [-Wunused-local-typedefs]
>  1588 | } HEAD, *PHEAD;
>       |          ^~~~~
> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/java.desktop/windows/native/libawt/windows/awt_Font.cpp:1595:11: warning: typedef 'PENTRY' locally defined but not used [-Wunused-local-typedefs]
>  1595 | } ENTRY, *PENTRY;
>       |           ^~~~~~
> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/java.desktop/windows/...

Julian Waters has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'openjdk:master' into awt
 - 8342869

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/21655/files
  - new: https://git.openjdk.org/jdk/pull/21655/files/ee4d1bb5..90903171

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21655&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21655&range=00-01

  Stats: 1560860 lines in 20249 files changed: 770956 ins; 654744 del; 135160 mod
  Patch: https://git.openjdk.org/jdk/pull/21655.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21655/head:pull/21655

PR: https://git.openjdk.org/jdk/pull/21655