Generate executable in current directory

Makefile

@@ -2,12 +2,11 @@ CC = gcc
 CFLAGS = -g -Wall
 SRC = src
 REQ = $(SRC)/lexer.l $(SRC)/parser.y $(SRC)/calculator.c $(SRC)/colour.c
-BIN = bin
 
 ifeq ($(OS),WINDOWS_NT)
 	CFLAGS += -D WIN32
 endif
 calculator : $(REQ)
 	bison -d $(SRC)/parser.y
 	flex -o calculator.lex.c $(SRC)/lexer.l
-	$(CC) $(CFLAGS) parser.tab.c calculator.lex.c $(SRC)/calculator.c $(SRC)/colour.c -o $(BIN)/$@
+	$(CC) $(CFLAGS) parser.tab.c calculator.lex.c $(SRC)/calculator.c $(SRC)/colour.c -o $@