add Makefile for building centos version of merge_pip

+CXX = -O2 -Wall -D__STDC_CONSTANT_MACROS
+SRCDIR = pip
+OBJDIR = obj
+BINDIR = bin
+
+SRCS = AudioDecoder.cpp  AVDecoder.cpp  AVTranscoder.cpp  merge_pip.cpp  tools.cpp  VideoDecoder.cpp
+OBJS = $(SRCS:%.cpp=$(OBJDIR)/%.o)
+
+LIBS =  avfilter avdevice avformat avcodec swresample avutil pthread  rtmp m z x264  swscale fdk-aac postproc swresample  ogg speex ssl crypto dl rt
+LIBDIRS = /home/hubin/ffmpeg-thin/build-ffmpeg/build/lib/
+#LIBDIRS = /home/hubin/ffmpeg_build/lib/
+LIBFLAGS = $(LIBS:%=-l%)
+LIBDIRFLAGS = $(LIBDIRS:%=-L%)
+
+INCFLAGS = -Iinclude -I/home/hubin/ffmpeg-thin/build-ffmpeg/build/include
+
+BIN_TRGTS = $(BINDIR)/merge_pip
+
+LDFLAGS = $(LIBFLAGS) $(LIBDIRFLAGS)
+CXXFLAGS = $(INCFLAGS)
+
+all: $(BIN_TRGTS)
+
+$(BIN_TRGTS): $(OBJS)
+	@mkdir -p $(@D)
+	g++ $(CXX) $^ -o $@ $(CXXFLAGS) $(LDFLAGS)
+
+$(OBJDIR)/%.o : $(SRCDIR)/%.cpp
+	@mkdir -p $(@D)
+	g++ $(CXX) -c -Iinclude $< -o $@ $(CXXFLAGS)
+
+clean:
+	rm -f $(OBJDIR)/*.o $(BIN_TRGTS)