RFR: 8342870: Errors related to unused code on Windows after 8339120 in accessibility [v6]

[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/jdk.accessibility/windows/native/jabswitch/jabswitch.cpp: In function 'int regEnable()':
> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/jdk.accessibility/windows/native/jabswitch/jabswitch.cpp:334:14: warning: unused variable 'freeData' [-Wunused-variable]
>   334 |         bool freeData = false;
>       |              ^~~~~~~~
> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/jdk.accessibility/windows/native/jabswitch/jabswitch.cpp:326:11: warning: unused variable 'retval' [-Wunused-variable]
>   326 |     DWORD retval = -1;
>       |           ^~~~~~
> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/jdk.accessibility/windows/native/jabswitch/jabswitch.cpp: In function 'int regDeleteValue(HKEY, LPCWSTR)':
> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/jdk.accessibility/windows/native/jabswitch/jabswitch.cpp:379:14: warning: unused variable 'freeData' [-Wunused-variable]
>   379 |         bool freeData = false;
>       |              ^~~~~~~~
> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/jdk.accessibility/windows/native/jabswitch/jabswitch.cpp:367:11: warning: unused variable 'retval' [-Wunused-variable]
>   367 |     DWORD retval = -1;
>       |           ^~~~~~
> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/jdk.accessibility/windows/native/bridge/AccessBridgeCalls.c: In function 'shutdownAccessBridge':
> C:/users/vertig0/downloads/eclipse-committers-2023-12-r-win32-x86_64/workspace/jdk/src/jdk.accessibi...

Julian Waters has updated the pull request incrementally with two additional commits since the last revision:

 - Typo in AccessBridgeCalls.c
 - Fix AccessBridgeCalls.c

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/21656/files
  - new: https://git.openjdk.org/jdk/pull/21656/files/f975dfa2..47b168a3

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21656&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21656&range=04-05

  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/21656.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21656/head:pull/21656

PR: https://git.openjdk.org/jdk/pull/21656