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