cannot build libc on old linux: faccessat.cpp:27:2: error: "faccessat2 syscall is not available." #163091
Description
fails on Ubuntu focal and debian bullseye
FAILED: libc/src/unistd/linux/CMakeFiles/libc.src.unistd.linux.faccessat.dir/faccessat.cpp.o
/build/source/build-llvm/./bin/clang++ --target=x86_64-pc-linux-gnu -DLIBC_NAMESPACE=__llvm_libc_22_0_0_ -I/build/source/libc -isystem libc/include -fstack-protector-strong -Wformat -Werror=format-security -Wno-unused-command-line-argument -Wdate-time -D_FORTIFY_SOURCE=2 -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 -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wno-pass-failed -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -fdebug-prefix-map=/build/source/build-llvm/runtimes/runtimes-bins=../../../ -fdebug-prefix-map=/build/source/= -no-canonical-prefixes -ffile-prefix-map=/build/source/build-llvm/runtimes/runtimes-bins=../../../ -ffile-prefix-map=/build/source/= -no-canonical-prefixes -O3 -DNDEBUG -DLIBC_QSORT_IMPL=LIBC_QSORT_QUICK_SORT -DLIBC_ADD_NULL_CHECKS -DLIBC_ERRNO_MODE=LIBC_ERRNO_MODE_DEFAULT -DLIBC_THREAD_MODE=LIBC_THREAD_MODE_PLATFORM -fpie -ffixed-point -fno-builtin -fno-exceptions -fno-lax-vector-conversions -fno-unwind-tables -fno-asynchronous-unwind-tables -fno-rtti -ftrivial-auto-var-init=pattern -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -Wall -Wextra -Werror -Wconversion -Wno-sign-conversion -Wdeprecated -Wno-c99-extensions -Wno-gnu-imaginary-constant -Wno-pedantic -Wimplicit-fallthrough -Wwrite-strings -Wextra-semi -Wnewline-eof -Wnonportable-system-include-path -Wstrict-prototypes -Wthread-safety -Wglobal-constructors -DLIBC_COPT_PUBLIC_PACKAGING -std=gnu++17 -MD -MT libc/src/unistd/linux/CMakeFiles/libc.src.unistd.linux.faccessat.dir/faccessat.cpp.o -MF libc/src/unistd/linux/CMakeFiles/libc.src.unistd.linux.faccessat.dir/faccessat.cpp.o.d -o libc/src/unistd/linux/CMakeFiles/libc.src.unistd.linux.faccessat.dir/faccessat.cpp.o -c /build/source/libc/src/unistd/linux/faccessat.cpp
/build/source/libc/src/unistd/linux/faccessat.cpp:27:2: error: "faccessat2 syscall is not available."
27 | #error "faccessat2 syscall is not available."
| ^
I am just going to disable libc for these archs. Opening in case others sees that