cc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations math/M_SQRT1_2l.c -o math/M_SQRT1_2l -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lintl -lcrypt -latomic
math/M_SQRT1_2l.c:8:26: error: 'M_SQRT1_2l' undeclared here (not in a function); did you mean 'M_SQRT1_2'?
    8 | long double  const foo = M_SQRT1_2l;
      |                          ^~~~~~~~~~
      |                          M_SQRT1_2