build: explicit CMake targets; move receiver pipeline out of shared

tests/test_config.c

@@ -4,6 +4,7 @@
 #include "multiprocessing.h"
 #include "protocol.h"
 #include "queue.h"
+#include "receiver_pipeline.h"
 #include "test_utils.h"
 #include "utils.h"
 #include <signal.h>

tests/test_multiprocessing.c

@@ -3,6 +3,7 @@
 #include "config.h"
 #include "protocol.h"
 #include "queue.h"
+#include "receiver_pipeline.h"
 #include "utils.h"
 #include "test_utils.h"
 #include <stdio.h>