cc -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations wchar/putwchar.c -o wchar/putwchar -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lintl -liconv
wchar/putwchar.c:5:26: error: ‘putwchar’ undeclared here (not in a function)
    5 | wint_t (*foo)(wchar_t) = putwchar;
      |                          ^~~~~~~~