cc -O2 -pthread -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations stdlib/setkey.c -o stdlib/setkey -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lintl -lcrypt stdlib/setkey.c:11:29: error: initialization of 'void (*)(const char *)' from incompatible pointer type 'int (*)(const char *)' [-Werror=incompatible-pointer-types] 11 | void (*foo)(const char *) = setkey; | ^~~~~~ cc1: all warnings being treated as errors