cc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations math/acosl.c -o math/acosl -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lintl -liconv
math/acosl.c:5:35: error: ‘acosl’ undeclared here (not in a function); did you mean ‘acosf’?
    5 | long double (*foo)(long double) = acosl;
      |                                   ^~~~~
      |                                   acosf