Bug ID: JDK-8347649 Build fails by clang after JDK-8313396

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Configure command:
bash configure --with-toolchain-type=clang --with-debug-level=fastdebug --with-toolchain-path=~/software/acc/x86_64/bin

Make command:
time make images test-image &> build/make.log

Make output:
=== Output from failing command(s) repeated here ===
* For target hotspot_variant-server_libjvm_objs_precompiled_precompiled.hpp.pch:
In file included from /home/yansendao/git/jdk-asan-clang/src/hotspot/share/precompiled/precompiled.hpp:34:
In file included from /home/yansendao/git/jdk-asan-clang/src/hotspot/share/classfile/classLoaderData.hpp:28:
In file included from /home/yansendao/git/jdk-asan-clang/src/hotspot/share/memory/allocation.hpp:29:
In file included from /home/yansendao/git/jdk-asan-clang/src/hotspot/share/nmt/memTag.hpp:28:
In file included from /home/yansendao/git/jdk-asan-clang/src/hotspot/share/utilities/globalDefinitions.hpp:30:
In file included from /home/yansendao/git/jdk-asan-clang/src/hotspot/share/utilities/forbiddenFunctions.hpp:38:
/home/yansendao/git/jdk-asan-clang/src/hotspot/os/posix/forbiddenFunctions_posix.hpp:43:1: error: attribute declaration must precede definition [-Werror,-Wignored-attributes]
   43 | FORBID_C_FUNCTION(char* realpath(const char*, char*), "use os::realpath");
      | ^
/home/yansendao/git/jdk-asan-clang/src/hotspot/share/utilities/compilerWarnings.hpp:109:18: note: expanded from macro 'FORBID_C_FUNCTION'
  109 |   extern "C" { [[deprecated(Alternative)]] Signature; }
      |                  ^
/usr/include/bits/stdlib.h:37:8: note: previous definition is here
   37 | __NTH (realpath (const char *__restrict __name, char *__restrict __resolved))
      |        ^
   ... (rest of output omitted)

This doesn't seem to be new behavior in clang, so changing "clang17" to just "clang" in the summary. It affects building with clang and using libstdc++. libstdc++ has an inline definition of realpath, to support _FORTIFY_SOURCE. libc++ seems to not have such an inline definition. That's why this didn't show up in my testing of JDK-8313396, which wasn't tested with building with clang on linux.
06-04-2025
This looks to me like a clang bug. I can't find any justification for the warning in the standard, and it interferes with what seem like standard-compliant uses.
18-03-2025
Close this issue as JDK-8313396 has been backouted.
15-01-2025
Caused by JDK-8313396
14-01-2025
A pull request was submitted for review. Branch: master URL: https://git.openjdk.org/jdk/pull/23102 Date: 2025-01-14 12:51:56 +0000
14-01-2025

Relates :	JDK-8347720 - [BACKOUT] Portable implementation of FORBID_C_FUNCTION and ALLOW_C_FUNCTION
Relates :	JDK-8313396 - Portable implementation of FORBID_C_FUNCTION and ALLOW_C_FUNCTION
Relates :	JDK-8347719 - [REDO] Portable implementation of FORBID_C_FUNCTION and ALLOW_C_FUNCTION