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