/opt/IBM/openxlC/17.1.1/bin/ibm-clang -pthread -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations math/M_PHIl.c -o math/M_PHIl -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -latomic math/M_PHIl.c:8:26: error: use of undeclared identifier 'M_PHIl' long double const foo = M_PHIl; ^ 1 error generated.