[compiler-rt] [compiler-rt][XRay] Make `xray_interface.h` C compliant (PR #140068)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-ppc64le-linux-multistage` running on `ppc64le-clang-multistage-test` while building `compiler-rt` at step 5 "ninja check 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/76/builds/9949

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (ninja check 1) failure: stage 1 checked (failure)
******************** TEST 'XRay-powerpc64le-linux :: TestCases/Posix/patching-unpatching.c' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage1/./bin/clang  -fxray-instrument  -m64 -fno-function-sections  -fxray-instrument -std=c23 /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/llvm/compiler-rt/test/xray/TestCases/Posix/patching-unpatching.c -o /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage1/runtimes/runtimes-bins/compiler-rt/test/xray/POWERPC64LELinuxConfig/TestCases/Posix/Output/patching-unpatching.c.tmp # RUN: at line 4
+ /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage1/./bin/clang -fxray-instrument -m64 -fno-function-sections -fxray-instrument -std=c23 /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/llvm/compiler-rt/test/xray/TestCases/Posix/patching-unpatching.c -o /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage1/runtimes/runtimes-bins/compiler-rt/test/xray/POWERPC64LELinuxConfig/TestCases/Posix/Output/patching-unpatching.c.tmp
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage1/lib/clang/21/lib/powerpc64le-unknown-linux-gnu/libclang_rt.xray-basic.a(xray_basic_logging.cpp.o): In function `__xray::basicLoggingInit(unsigned long, unsigned long, void*, unsigned long)::$_0::__invoke()':
/usr/include/sys/platform/gthr-default.h:107: undefined reference to `std::__throw_system_error(int)'
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage1/lib/clang/21/lib/powerpc64le-unknown-linux-gnu/libclang_rt.xray-basic.a(xray_basic_logging.cpp.o): In function `__xray::getLog()::$_0::__invoke()':
/usr/include/sys/platform/gthr-default.h:107: undefined reference to `std::__throw_system_error(int)'
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage1/lib/clang/21/lib/powerpc64le-unknown-linux-gnu/libclang_rt.xray-fdr.a(xray_fdr_logging.cpp.o): In function `__xray::fdrCommonHeaderInfo()::$_0::__invoke()':
/usr/lib/gcc/ppc64le-redhat-linux/8/../../../../include/c++/8/gthr-default.h:107: undefined reference to `std::__throw_system_error(int)'
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage1/lib/clang/21/lib/powerpc64le-unknown-linux-gnu/libclang_rt.xray-fdr.a(xray_fdr_logging.cpp.o): In function `__xray::fdrLoggingInit(unsigned long, unsigned long, void*, unsigned long)::$_0::__invoke()':
/usr/lib/gcc/ppc64le-redhat-linux/8/../../../../include/c++/8/gthr-default.h:107: undefined reference to `std::__throw_system_error(int)'
clang: error: linker command failed with exit code 1 (use -v to see invocation)

--

********************

Step 11 (ninja check 2) failure: stage 2 checked (failure)
******************** TEST 'XRay-powerpc64le-linux :: TestCases/Posix/patching-unpatching.c' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage2/./bin/clang  -fxray-instrument  -m64 -fno-function-sections  -fxray-instrument -std=c23 /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/llvm/compiler-rt/test/xray/TestCases/Posix/patching-unpatching.c -o /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage2/runtimes/runtimes-bins/compiler-rt/test/xray/POWERPC64LELinuxConfig/TestCases/Posix/Output/patching-unpatching.c.tmp # RUN: at line 4
+ /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage2/./bin/clang -fxray-instrument -m64 -fno-function-sections -fxray-instrument -std=c23 /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/llvm/compiler-rt/test/xray/TestCases/Posix/patching-unpatching.c -o /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage2/runtimes/runtimes-bins/compiler-rt/test/xray/POWERPC64LELinuxConfig/TestCases/Posix/Output/patching-unpatching.c.tmp
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage2/lib/clang/21/lib/powerpc64le-unknown-linux-gnu/libclang_rt.xray-basic.a(xray_basic_logging.cpp.o): In function `__xray::basicLoggingInit(unsigned long, unsigned long, void*, unsigned long)::$_0::__invoke()':
/usr/include/sys/platform/gthr-default.h:107: undefined reference to `std::__throw_system_error(int)'
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage2/lib/clang/21/lib/powerpc64le-unknown-linux-gnu/libclang_rt.xray-basic.a(xray_basic_logging.cpp.o): In function `__xray::getLog()::$_0::__invoke()':
/usr/include/sys/platform/gthr-default.h:107: undefined reference to `std::__throw_system_error(int)'
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage2/lib/clang/21/lib/powerpc64le-unknown-linux-gnu/libclang_rt.xray-fdr.a(xray_fdr_logging.cpp.o): In function `__xray::fdrCommonHeaderInfo()::$_0::__invoke()':
/usr/lib/gcc/ppc64le-redhat-linux/8/../../../../include/c++/8/gthr-default.h:107: undefined reference to `std::__throw_system_error(int)'
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage2/lib/clang/21/lib/powerpc64le-unknown-linux-gnu/libclang_rt.xray-fdr.a(xray_fdr_logging.cpp.o): In function `__xray::fdrLoggingInit(unsigned long, unsigned long, void*, unsigned long)::$_0::__invoke()':
/usr/lib/gcc/ppc64le-redhat-linux/8/../../../../include/c++/8/gthr-default.h:107: undefined reference to `std::__throw_system_error(int)'
clang: error: linker command failed with exit code 1 (use -v to see invocation)

--

********************


```

</details>

https://github.com/llvm/llvm-project/pull/140068