x86_64-managarm-gcc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations math/yn.c -o math/yn -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lintl -liconv
math/yn.c:11:30: error: ‘yn’ undeclared here (not in a function)
   11 | double (*foo)(int, double) = yn;
      |                              ^~