Related to https://reviews.llvm.org/D127571

llvm-libc_riscv_cmake

$ CC=clang CXX=clang++ cmake -DLLVM_ENABLE_RUNTIMES=libc -DCMAKE_INSTALL_PREFIX=/home/advancedwebdeveloper/libc_install -DCMAKE_BUILD_TYPE=MinSizeRel ../llvm-project-main/runtimes
-- The C compiler identification is Clang 12.0.0
-- The CXX compiler identification is Clang 12.0.0
-- The ASM compiler identification is Clang
-- Found assembler: /usr/bin/clang
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/clang - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/clang++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Could NOT find LLVM (missing: LLVM_DIR)
-- Could NOT find Clang (missing: Clang_DIR)
-- Performing Test LLVM_RUNTIMES_LINKING_WORKS
-- Performing Test LLVM_RUNTIMES_LINKING_WORKS - Success
-- Performing Test CXX_SUPPORTS_NOSTDLIBXX_FLAG
-- Performing Test CXX_SUPPORTS_NOSTDLIBXX_FLAG - Success
-- Performing Test CXX_SUPPORTS_NOSTDINCXX_FLAG
-- Performing Test CXX_SUPPORTS_NOSTDINCXX_FLAG - Success
-- Linker detection: GNU ld
-- Performing Test SUPPORTS_FVISIBILITY_INLINES_HIDDEN_FLAG
-- Performing Test SUPPORTS_FVISIBILITY_INLINES_HIDDEN_FLAG - Success
-- Performing Test C_SUPPORTS_WERROR_DATE_TIME
-- Performing Test C_SUPPORTS_WERROR_DATE_TIME - Success
-- Performing Test CXX_SUPPORTS_WERROR_DATE_TIME
-- Performing Test CXX_SUPPORTS_WERROR_DATE_TIME - Success
-- Performing Test C_SUPPORTS_WERROR_UNGUARDED_AVAILABILITY_NEW
-- Performing Test C_SUPPORTS_WERROR_UNGUARDED_AVAILABILITY_NEW - Success
-- Performing Test CXX_SUPPORTS_WERROR_UNGUARDED_AVAILABILITY_NEW
-- Performing Test CXX_SUPPORTS_WERROR_UNGUARDED_AVAILABILITY_NEW - Success
-- Performing Test CXX_SUPPORTS_MISSING_FIELD_INITIALIZERS_FLAG
-- Performing Test CXX_SUPPORTS_MISSING_FIELD_INITIALIZERS_FLAG - Success
-- Performing Test C_SUPPORTS_IMPLICIT_FALLTHROUGH_FLAG
-- Performing Test C_SUPPORTS_IMPLICIT_FALLTHROUGH_FLAG - Success
-- Performing Test CXX_SUPPORTS_IMPLICIT_FALLTHROUGH_FLAG
-- Performing Test CXX_SUPPORTS_IMPLICIT_FALLTHROUGH_FLAG - Success
-- Performing Test C_SUPPORTS_COVERED_SWITCH_DEFAULT_FLAG
-- Performing Test C_SUPPORTS_COVERED_SWITCH_DEFAULT_FLAG - Success
-- Performing Test CXX_SUPPORTS_COVERED_SWITCH_DEFAULT_FLAG
-- Performing Test CXX_SUPPORTS_COVERED_SWITCH_DEFAULT_FLAG - Success
-- Performing Test CXX_SUPPORTS_CLASS_MEMACCESS_FLAG
-- Performing Test CXX_SUPPORTS_CLASS_MEMACCESS_FLAG - Failed
-- Performing Test CXX_SUPPORTS_NOEXCEPT_TYPE_FLAG
-- Performing Test CXX_SUPPORTS_NOEXCEPT_TYPE_FLAG - Success
-- Performing Test CXX_WONT_WARN_ON_FINAL_NONVIRTUALDTOR
-- Performing Test CXX_WONT_WARN_ON_FINAL_NONVIRTUALDTOR - Success
-- Performing Test CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG
-- Performing Test CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG - Success
-- Performing Test CXX_WSUGGEST_OVERRIDE_ALLOWS_ONLY_FINAL
-- Performing Test CXX_WSUGGEST_OVERRIDE_ALLOWS_ONLY_FINAL - Success
-- Performing Test C_WCOMMENT_ALLOWS_LINE_WRAP
-- Performing Test C_WCOMMENT_ALLOWS_LINE_WRAP - Failed
-- Performing Test C_SUPPORTS_STRING_CONVERSION_FLAG
-- Performing Test C_SUPPORTS_STRING_CONVERSION_FLAG - Success
-- Performing Test CXX_SUPPORTS_STRING_CONVERSION_FLAG
-- Performing Test CXX_SUPPORTS_STRING_CONVERSION_FLAG - Success
-- Performing Test C_SUPPORTS_MISLEADING_INDENTATION_FLAG
-- Performing Test C_SUPPORTS_MISLEADING_INDENTATION_FLAG - Success
-- Performing Test CXX_SUPPORTS_MISLEADING_INDENTATION_FLAG
-- Performing Test CXX_SUPPORTS_MISLEADING_INDENTATION_FLAG - Success
-- Performing Test C_SUPPORTS_FNO_FUNCTION_SECTIONS
-- Performing Test C_SUPPORTS_FNO_FUNCTION_SECTIONS - Success
-- Performing Test C_SUPPORTS_FFUNCTION_SECTIONS
-- Performing Test C_SUPPORTS_FFUNCTION_SECTIONS - Success
-- Performing Test CXX_SUPPORTS_FFUNCTION_SECTIONS
-- Performing Test CXX_SUPPORTS_FFUNCTION_SECTIONS - Success
-- Performing Test C_SUPPORTS_FDATA_SECTIONS
-- Performing Test C_SUPPORTS_FDATA_SECTIONS - Success
-- Performing Test CXX_SUPPORTS_FDATA_SECTIONS
-- Performing Test CXX_SUPPORTS_FDATA_SECTIONS - Success
-- Looking for os_signpost_interval_begin
-- Looking for os_signpost_interval_begin - not found
-- Found Python3: /usr/bin/python3.9 (found version "3.9.5") found components: Interpreter 
-- Set COMPILER_RESOURCE_DIR to /usr/lib/llvm-12/lib/clang/12.0.0 using --print-resource-dir
-- Set CPU features: <end_of_feature_list>
-- Skipping libc entrypoint libc.src.fenv.feholdexcept.
-- Skipping libc entrypoint libc.src.fenv.feenableexcept.
-- Skipping libc entrypoint libc.src.fenv.fedisableexcept.
-- Skipping libc entrypoint libc.src.fenv.fegetexcept.
-- Skipping libc entrypoint libc.src.math.fma.
-- Skipping libc entrypoint libc.src.math.cos.
-- Skipping libc entrypoint libc.src.math.sin.
-- Skipping libc entrypoint libc.src.math.tan.
-- Skipping libc entrypoint libc.src.stdlib.getenv.
-- Skipping libc entrypoint libc.src.pthread.pthread_attr_init.
-- Skipping libc entrypoint libc.src.pthread.pthread_attr_destroy.
-- Skipping libc entrypoint libc.src.pthread.pthread_attr_getdetachstate.
-- Skipping libc entrypoint libc.src.pthread.pthread_attr_setdetachstate.
-- Skipping libc entrypoint libc.src.pthread.pthread_attr_getguardsize.
-- Skipping libc entrypoint libc.src.pthread.pthread_attr_setguardsize.
-- Skipping libc entrypoint libc.src.pthread.pthread_attr_getstacksize.
-- Skipping libc entrypoint libc.src.pthread.pthread_attr_setstacksize.
-- Skipping libc entrypoint libc.src.pthread.pthread_attr_getstack.
-- Skipping libc entrypoint libc.src.pthread.pthread_attr_setstack.
-- Skipping libc entrypoint libc.src.pthread.pthread_mutexattr_init.
-- Skipping libc entrypoint libc.src.pthread.pthread_mutexattr_gettype.
-- Skipping libc entrypoint libc.src.pthread.pthread_mutexattr_settype.
-- Skipping libc entrypoint libc.src.pthread.pthread_mutexattr_destroy.
-- Skipping libc entrypoint libc.src.pthread.pthread_mutexattr_getrobust.
-- Skipping libc entrypoint libc.src.pthread.pthread_mutexattr_setrobust.
-- Skipping libc entrypoint libc.src.pthread.pthread_mutexattr_getpshared.
-- Skipping libc entrypoint libc.src.pthread.pthread_mutexattr_setpshared.
-- Skipping libc entrypoint libc.src.pthread.pthread_mutex_init.
-- Skipping libc entrypoint libc.src.pthread.pthread_mutex_destroy.
-- Skipping libc entrypoint libc.src.pthread.pthread_mutex_lock.
-- Skipping libc entrypoint libc.src.pthread.pthread_mutex_unlock.
-- Skipping libc entrypoint libc.src.pthread.pthread_create.
-- Skipping libc entrypoint libc.src.pthread.pthread_join.
-- Skipping unittest libc.test.src.fenv.feenableexcept_test as it has missing deps: libc.src.fenv.fedisableexceptlibc.src.fenv.feenableexceptlibc.src.fenv.fegetexcept.
-- Skipping unittest libc.test.src.fenv.feholdexcept_test as it has missing deps: libc.src.fenv.feholdexcept.
-- Skipping unittest libc.test.src.math.cos_test as it has missing deps: libc.src.math.cos.
-- Skipping unittest libc.test.src.math.sin_test as it has missing deps: libc.src.math.sin.
-- Skipping unittest libc.test.src.math.fma_test as it has missing deps: libc.src.math.fma.
-- Skipping unittest libc.test.src.math.tan_test as it has missing deps: libc.src.math.tan.
-- check-runtimes does nothing.
-- Configuring done
-- Generating done
-- Build files have been written to: /home/advancedwebdeveloper/libc_build