How to compile it?

[Jawadi61]

/usr/bin/ld: /tmp/cckhqlgW.o: in function main': BurgerBuddies.c:(.text+0x4e): undefined reference to sem_init'
/usr/bin/ld: BurgerBuddies.c:(.text+0x64): undefined reference to sem_init' /usr/bin/ld: BurgerBuddies.c:(.text+0x7a): undefined reference to sem_init'
/usr/bin/ld: BurgerBuddies.c:(.text+0x90): undefined reference to sem_init' /usr/bin/ld: BurgerBuddies.c:(.text+0xa6): undefined reference to sem_init'
/usr/bin/ld: /tmp/cckhqlgW.o:BurgerBuddies.c:(.text+0xbc): more undefined references to sem_init' follow /usr/bin/ld: /tmp/cckhqlgW.o: in function main':
BurgerBuddies.c:(.text+0x125): undefined reference to pthread_create' /usr/bin/ld: BurgerBuddies.c:(.text+0x14b): undefined reference to sem_wait'
/usr/bin/ld: BurgerBuddies.c:(.text+0x1ac): undefined reference to pthread_create' /usr/bin/ld: BurgerBuddies.c:(.text+0x1d2): undefined reference to sem_wait'
/usr/bin/ld: BurgerBuddies.c:(.text+0x233): undefined reference to pthread_create' /usr/bin/ld: BurgerBuddies.c:(.text+0x259): undefined reference to sem_wait'
/usr/bin/ld: BurgerBuddies.c:(.text+0x27e): undefined reference to sem_destroy' /usr/bin/ld: BurgerBuddies.c:(.text+0x2a2): undefined reference to pthread_join'
/usr/bin/ld: BurgerBuddies.c:(.text+0x317): undefined reference to sem_post' /usr/bin/ld: BurgerBuddies.c:(.text+0x345): undefined reference to sem_post'
/usr/bin/ld: BurgerBuddies.c:(.text+0x38e): undefined reference to pthread_join' /usr/bin/ld: BurgerBuddies.c:(.text+0x3f3): undefined reference to pthread_join'
/usr/bin/ld: /tmp/cckhqlgW.o: in function cook_run': BurgerBuddies.c:(.text+0x4ae): undefined reference to sem_post'
/usr/bin/ld: BurgerBuddies.c:(.text+0x4ba): undefined reference to sem_wait' /usr/bin/ld: BurgerBuddies.c:(.text+0x509): undefined reference to sem_wait'
/usr/bin/ld: BurgerBuddies.c:(.text+0x539): undefined reference to sem_post' /usr/bin/ld: BurgerBuddies.c:(.text+0x55c): undefined reference to sem_post'
/usr/bin/ld: /tmp/cckhqlgW.o: in function cashier_run': BurgerBuddies.c:(.text+0x5c7): undefined reference to sem_init'
/usr/bin/ld: BurgerBuddies.c:(.text+0x5dd): undefined reference to sem_init' /usr/bin/ld: BurgerBuddies.c:(.text+0x604): undefined reference to sem_post'
/usr/bin/ld: BurgerBuddies.c:(.text+0x610): undefined reference to sem_wait' /usr/bin/ld: BurgerBuddies.c:(.text+0x662): undefined reference to sem_post'
/usr/bin/ld: BurgerBuddies.c:(.text+0x66e): undefined reference to sem_wait' /usr/bin/ld: BurgerBuddies.c:(.text+0x6dc): undefined reference to sem_wait'
/usr/bin/ld: BurgerBuddies.c:(.text+0x6e8): undefined reference to sem_wait' /usr/bin/ld: BurgerBuddies.c:(.text+0x718): undefined reference to sem_post'
/usr/bin/ld: BurgerBuddies.c:(.text+0x724): undefined reference to sem_post' /usr/bin/ld: BurgerBuddies.c:(.text+0x77b): undefined reference to sem_post'
/usr/bin/ld: BurgerBuddies.c:(.text+0x7a4): undefined reference to sem_destroy' /usr/bin/ld: BurgerBuddies.c:(.text+0x7b0): undefined reference to sem_destroy'
/usr/bin/ld: /tmp/cckhqlgW.o: in function customer_run': BurgerBuddies.c:(.text+0x82b): undefined reference to sem_post'
/usr/bin/ld: BurgerBuddies.c:(.text+0x86c): undefined reference to sem_wait' /usr/bin/ld: BurgerBuddies.c:(.text+0x878): undefined reference to sem_post'
/usr/bin/ld: BurgerBuddies.c:(.text+0x884): undefined reference to sem_wait' /usr/bin/ld: BurgerBuddies.c:(.text+0x8b0): undefined reference to sem_post'
/usr/bin/ld: BurgerBuddies.c:(.text+0x926): undefined reference to sem_post' /usr/bin/ld: BurgerBuddies.c:(.text+0x932): undefined reference to sem_wait'
collect2: error: ld returned 1 exit status

[bouzenaali]

just run make all in the project main directory and everything will be compiled automatically