cc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations wchar/ungetwc.c -o wchar/ungetwc -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lintl -liconv
wchar/ungetwc.c:5:33: error: ‘ungetwc’ undeclared here (not in a function)
    5 | wint_t (*foo)(wint_t, FILE *) = ungetwc;
      |                                 ^~~~~~~