RFR: 8346436: Compilation with clang fails [v2]

[Jan Kratochvil]

> clang-18.1.8-1.fc40.x86_64
> Fedora 40 x86_64
> fbd76ca8edd756ff2ebbc9f6477cc1a827df67b0
> 
> 
> src/java.desktop/unix/native/libawt_xawt/xawt/XToolkit.c:695:9: error: ignoring return value of function declared with 'warn_unused_result' attribute [-Werror,-Wunused-result]
>   695 | write ( AWT_WRITEPIPE, &wakeUp_char, 1 );
>       | ^~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> src/java.desktop/unix/native/libsplashscreen/splashscreen_sys.c:375:9: error: ignoring return value of function declared with 'warn_unused_result' attribute [-Werror,-Wunused-result]
>   375 | write(splash->controlpipe[1], &code, 1);
>       | ^~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> src/java.desktop/unix/native/libsplashscreen/splashscreen_sys.c:713:5: error: ignoring return value of function declared with 'warn_unused_result' attribute [-Werror,-Wunused-result]
>   713 | pipe(splash->controlpipe);
>       | ^~~~ ~~~~~~~~~~~~~~~~~~~
> src/jdk.crypto.cryptoki/share/native/libj2pkcs11/j2secmod.h:45:9: error: 'dprintf' macro redefined [-Werror,-Wmacro-redefined]
>    45 | #define dprintf(s)
>       | ^
> /usr/include/bits/stdio2.h:121:12: note: previous definition is here
>   121 | # define dprintf(fd, ...) \
>       | ^
> src/java.smartcardio/share/native/libj2pcsc/pcsc.c:48:9: error: 'dprintf' macro redefined [-Werror,-Wmacro-redefined]
>    48 | #define dprintf(s)
>       | ^
> /usr/include/bits/stdio2.h:121:12: note: previous definition is here
>   121 | # define dprintf(fd, ...) \
>       | ^

Jan Kratochvil 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 three additional commits since the last revision:

 - Use only (void) casts
 - Merge branch 'master' into clangbuild
 - 8346436: Compilation with clang fails

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22794/files
  - new: https://git.openjdk.org/jdk/pull/22794/files/3e81ab51..0e2ab3b7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22794&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22794&range=00-01

  Stats: 10553 lines in 262 files changed: 7856 ins; 1822 del; 875 mod
  Patch: https://git.openjdk.org/jdk/pull/22794.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22794/head:pull/22794

PR: https://git.openjdk.org/jdk/pull/22794