/opt/IBM/openxlC/17.1.1/bin/ibm-clang -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations unistd/setresgid.c -o unistd/setresgid -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -latomic
unistd/setresgid.c:11:35: error: use of undeclared identifier 'setresgid'
int (*foo)(gid_t, gid_t, gid_t) = setresgid;
                                  ^
1 error generated.