clang -O2  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations signal/str2sig.c -o signal/str2sig -D_POSIX_C_SOURCE=202405L  -lm  -lintl
signal/str2sig.c:5:51: error: use of undeclared identifier 'str2sig'
int (*foo)(const char *restrict, int *restrict) = str2sig;
                                                  ^
1 error generated.