(Makefile)~modified to be slightly more agnostic

I'm going to add recipes for other language implementations of certain
algorithms so as long as you have the correct background programs it
just requires a make call to run the program.

Makefile

@@ -3,11 +3,14 @@ CFLAGS=-pedantic -Wall -ggdb -fsanitize=address
 VFLAGS=--show-leak-kinds=all --leak-check=full
 OUT=
 
-$(OUT).out: $(OUT).cpp
+btree.out: btree.cpp
+	$(CC) $(CFLAGS) $^ -o $@
+
+list.out: list.cpp
 	$(CC) $(CFLAGS) $^ -o $@
 
 .PHONY: run
-run: $(OUT).out
+run: $(OUT)
 	./$^
 
 .PHONY: clean