Added a Makefile for better use

Makefile

@@ -0,0 +1,23 @@
+# Makefile for a simple C program
+
+# Compiler
+CC = gcc
+
+# Compiler flags
+CFLAGS = -g -Wall -std=c99 -pedantic
+
+# Source file
+SRC = njvm.c
+
+# Executable name
+TARGET = njvm
+
+# Default target
+all: 
+	$(CC) $(CFLAGS) -o $(TARGET) $(SRC)
+# Clean up
+clean:
+	rm -f $(OBJ) $(TARGET)
+
+run: all
+	./$(TARGET)