modify Makefile dependence

.drone.yml

@@ -6,5 +6,4 @@ steps:
   commands:
   - apt-get update
   - apt-get install -y libboost-test-dev
-  - mkdir obj
-  - make boosttest
+  - make boosttest

Makefile

@@ -20,9 +20,10 @@ else
 INC= -Iinclude
 LIB= -lboost_test_exec_monitor
 
-boosttest: obj/boosttest.o obj/script_parser.o
+boosttest: obj obj/boosttest.o obj/script_parser.o
 	g++ -o boosttest obj/boosttest.o obj/script_parser.o ${LIB}
-
+obj:
+	mkdir obj
 obj/boosttest.o: src/boosttest.cpp
 	g++ -o obj/boosttest.o src/boosttest.cpp -c ${INC}