cc -pipe -O   -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations math/M_PHI.c -o math/M_PHI -D_POSIX_C_SOURCE=202405L  -lm -lpthread -lrt  -lrt -lcrypt
math/M_PHI.c:8:21: error: 'M_PHI' undeclared here (not in a function); did you mean 'M_PI'?
 double  const foo = M_PHI;
                     ^~~~~
                     M_PI