cc -pthread -Wall -Wextra -Werror=implicit-function-declaration sys_ipc/ftok.c -o sys_ipc/ftok -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -lrt -lintl -liconv sys_ipc/ftok.c:4:10: fatal error: sys/ipc.h: No such file or directory 4 | #include | ^~~~~~~~~~~ compilation terminated.