hope this works

code/Makefile

@@ -1,13 +1,23 @@
 obj-m += lkm.o
 
+CC := gcc
+
 SOURCES := $(wildcard *.c)
 TARGETS := $(SOURCES:.c=.o)
 
+CFLAGS += -g
+CFLAGS += -O0
+CFLAGS += -Wall
+CFLAGS += -Wextra
+
 all: $(TARGETS)
 
 run: leak
 	./leak.o
 
+%.o: %.c
+	$(CC) $< $(CFLAGS) -o $@
+
 lkm:
 	make -C /lib/modules/$(shell uname -r)/build M=$(shell pwd) modules
 

code/leak.c

@@ -7,7 +7,7 @@
 #include <string.h>
 #include <unistd.h>
 
-#include "pipe_utils.h"
+#include "pipe_utils.c"
 
 // where does this come from?
 #define OBJS_PER_SLAB 42

code/pipe_utils.c

@@ -1,11 +1,8 @@
 #define _GNU_SOURCE
-#include <sys/socket.h>
 
 #include <fcntl.h>
 #include <unistd.h>
 
-#include "pipe_utils.h"
-
 void
 allocation_primitive(int fd[2])
 {

code/pipe_utils.h

@@ -1 +0,0 @@
-void allocation_primitive(int fd[2]);