[compiler-rt] [sanitizer_common] AND signals in BlockSignals instead of deleting (PR #113443)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-solaris11-sparcv9` running on `solaris11-sparcv9` while building `compiler-rt` at step 4 "build stage 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/13/builds/3259

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

```
Step 4 (build stage 1) failure: 'ninja -j8' (failure)
...
[2955/5540] Building CXX object projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_libignore.cpp.o
[2956/5540] Building CXX object projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_linux_s390.cpp.o
[2957/5540] Building CXX object projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_mac.cpp.o
[2958/5540] Building CXX object projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_netbsd.cpp.o
[2959/5540] Building CXX object projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_platform_limits_freebsd.cpp.o
[2960/5540] Building CXX object projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_platform_limits_linux.cpp.o
[2961/5540] Building CXX object projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_mutex.cpp.o
[2962/5540] Building CXX object projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_platform_limits_netbsd.cpp.o
[2963/5540] Building CXX object projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_platform_limits_posix.cpp.o
[2964/5540] Building CXX object projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_linux.cpp.o
FAILED: projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_linux.cpp.o 
/opt/llvm/19/bin/clang++ -DHAVE_RPC_XDR_H=1 -D_DEBUG -D_FILE_OFFSET_BITS=64 -D_GLIBCXX_ASSERTIONS -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/stage1/projects/compiler-rt/lib/sanitizer_common -I/opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/llvm/compiler-rt/lib/sanitizer_common -I/opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/stage1/include -I/opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/llvm/llvm/include -I/opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/llvm/llvm/include/llvm/Support/Solaris -I/opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/llvm/compiler-rt/lib/sanitizer_common/.. -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -Wall -Wno-unused-parameter  -O -DNDEBUG -m32 -fPIC -fno-builtin -fno-exceptions -fomit-frame-pointer -funwind-tables -fno-stack-protector -fno-sanitize=safe-stack -fvisibility=hidden -fno-lto -Wthread-safety -Wthread-safety-reference -Wthread-safety-beta -O3 -gline-tables-only -Wno-gnu -Wno-variadic-macros -Wno-c99-extensions -ftrivial-auto-var-init=pattern -nostdinc++ -Wno-format -fno-rtti -Wframe-larger-than=570 -Wglobal-constructors -std=c++17 -MD -MT projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_linux.cpp.o -MF projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_linux.cpp.o.d -o projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_linux.cpp.o -c /opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/llvm/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
/opt/llvm-buildbot/home/solaris11-sparcv9/clang-solaris11-sparcv9/llvm/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp:172:5: error: use of undeclared identifier 'internal_sigdelset'
  172 |     internal_sigdelset(&newset, signum);
      |     ^
1 error generated.
[2965/5540] Building CXX object projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_platform_limits_solaris.cpp.o
[2966/5540] Building CXX object projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_libc.cpp.o
[2967/5540] Building CXX object projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_posix.cpp.o
[2968/5540] Building CXX object lib/ExecutionEngine/Orc/CMakeFiles/LLVMOrcJIT.dir/ThreadSafeModule.cpp.o
[2969/5540] Building CXX object lib/ExecutionEngine/Orc/CMakeFiles/LLVMOrcJIT.dir/JITLinkRedirectableSymbolManager.cpp.o
[2970/5540] Building CXX object lib/ExecutionEngine/Orc/CMakeFiles/LLVMOrcJIT.dir/SpeculateAnalyses.cpp.o
[2971/5540] Building CXX object lib/ExecutionEngine/Orc/CMakeFiles/LLVMOrcJIT.dir/ReOptimizeLayer.cpp.o
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/113443