clang -O2  -Wall -Wextra -Werror=implicit-function-declaration semaphore/sem_timedwait.c -o semaphore/sem_timedwait -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm  -lintl
../out/minix/basic/semaphore/sem_timedwait.o: In function `main':
semaphore/sem_timedwait.c:(.text+0x313): undefined reference to `sem_init'
semaphore/sem_timedwait.c:(.text+0x34d): undefined reference to `sem_timedwait'
semaphore/sem_timedwait.c:(.text+0x371): undefined reference to `sem_timedwait'
clang: error: linker command failed with exit code 1 (use -v to see invocation)