implement basic string functions (memset, memcpy, etc)

Makefile

@@ -1,5 +1,5 @@
 # Define the object files
-OBJS = bin/boot.o bin/kernel.o bin/idt.o bin/isr.o bin/screen.o bin/utils.o
+OBJS = bin/boot.o bin/kernel.o bin/idt.o bin/isr.o bin/screen.o bin/utils.o bin/string.o
 
 # Define the compiler and assembler
 CC = gcc
@@ -39,6 +39,9 @@ bin/idt.o: src/idt.c
 bin/utils.o: src/utils.c
 	$(CC) $(CFLAGS) -c $< -o $@
 
+bin/string.o: src/string.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
 clean:
 	rm -rf bin/
 	rm -f $(OUTPUT)