clang -O2 -Wall -Wextra -Werror=implicit-function-declaration sys_msg/msgrcv.c -o sys_msg/msgrcv -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lintl ../out/minix/basic/sys_msg/msgrcv.o: In function `main': sys_msg/msgrcv.c:(.text+0x3e0): undefined reference to `msgget' sys_msg/msgrcv.c:(.text+0x41d): undefined reference to `msgsnd' sys_msg/msgrcv.c:(.text+0x44e): undefined reference to `msgrcv' ../out/minix/basic/sys_msg/msgrcv.o: In function `cleanup': sys_msg/msgrcv.c:(.text+0x54b): undefined reference to `__msgctl50' ../out/minix/basic/sys_msg/msgrcv.o: In function `on_signal': sys_msg/msgrcv.c:(.text+0x67f): undefined reference to `__msgctl50' clang: error: linker command failed with exit code 1 (use -v to see invocation)