clang -O2  -Wall -Wextra -Werror=implicit-function-declaration sys_msg/msgctl.c -o sys_msg/msgctl -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm  -lintl
sys_msg/msgctl.c:71:24: warning: & has lower precedence than !=; != will be evaluated first [-Wparentheses]
        if ( ds.msg_perm.mode & 0777 != 0600 )
                              ^~~~~~~~~~~~~~
sys_msg/msgctl.c:71:24: note: place parentheses around the '!=' expression to silence this warning
        if ( ds.msg_perm.mode & 0777 != 0600 )
                              ^
                                (           )
sys_msg/msgctl.c:71:24: note: place parentheses around the & expression to evaluate it first
        if ( ds.msg_perm.mode & 0777 != 0600 )
                              ^
             (                      )
1 warning generated.
../out/minix/basic/sys_msg/msgctl.o: In function `main':
sys_msg/msgctl.c:(.text+0x3e3): undefined reference to `msgget'
sys_msg/msgctl.c:(.text+0x408): undefined reference to `__msgctl50'
../out/minix/basic/sys_msg/msgctl.o: In function `cleanup':
sys_msg/msgctl.c:(.text+0x5cb): undefined reference to `__msgctl50'
../out/minix/basic/sys_msg/msgctl.o: In function `on_signal':
sys_msg/msgctl.c:(.text+0x6ff): undefined reference to `__msgctl50'
clang: error: linker command failed with exit code 1 (use -v to see invocation)