I get errors when compiling reveiver.c.

[DeVogelRyan]

This is the output I get in the console:
reveiver.c: In function ‘th4’:
reveiver.c:207:5: warning: ‘return’ with no value, in function returning non-void
207 | return;
| ^~~~~~
reveiver.c:170:7: note: declared here
170 | void *th4(void *ptr) {
| ^~~
reveiver.c:222:2: warning: ‘return’ with no value, in function returning non-void
222 | return;
| ^~~~~~
reveiver.c:170:7: note: declared here
170 | void *th4(void *ptr) {
| ^~~
/usr/bin/ld: /tmp/ccFIRJXj.o: in function AssembleFileFromPackets': reveiver.c:(.text+0x115): undefined reference to pthread_create'
/usr/bin/ld: reveiver.c:(.text+0x137): undefined reference to pthread_create' /usr/bin/ld: reveiver.c:(.text+0x14b): undefined reference to pthread_join'
/usr/bin/ld: reveiver.c:(.text+0x15c): undefined reference to `pthread_join'
collect2: error: ld returned 1 exit status