clang -O2 -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations stdio/vsscanf.c -o stdio/vsscanf -D_POSIX_C_SOURCE=202405L -lm -lintl stdio/vsscanf.c:5:67: error: implicitly declaring library function 'vsscanf' with type 'int (const char *restrict, const char *restrict, __builtin_va_list)' [-Werror] int (*foo)(const char *restrict, const char *restrict, va_list) = vsscanf; ^ stdio/vsscanf.c:5:67: note: include the header or explicitly provide a declaration for 'vsscanf' 1 error generated.