/opt/IBM/openxlC/17.1.1/bin/ibm-clang -pthread -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations unistd/_POSIX_TIMESTAMP_RESOLUTION.c -o unistd/_POSIX_TIMESTAMP_RESOLUTION -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -latomic unistd/_POSIX_TIMESTAMP_RESOLUTION.c:3:17: error: use of undeclared identifier '_POSIX_TIMESTAMP_RESOLUTION' int const foo = _POSIX_TIMESTAMP_RESOLUTION; ^ 1 error generated.