cc -pthread -Wall -Wextra -Werror=implicit-function-declaration utmpx/getutxid.c -o utmpx/getutxid -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -lrt -lintl -liconv utmpx/getutxid.c:5:10: fatal error: utmpx.h: No such file or directory 5 | #include | ^~~~~~~~~ compilation terminated.