/opt/IBM/openxlC/17.1.1/bin/ibm-clang -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations unistd/_Fork.c -o unistd/_Fork -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -latomic
unistd/_Fork.c:5:22: error: use of undeclared identifier '_Fork'
pid_t (*foo)(void) = _Fork;
                     ^
1 error generated.