注释，依赖，命令，（循环依赖），宏定义，宏定义外置；
2. Example：
http://www.opussoftware.com/tutorial/TutMakefile.htm
# This makefile compiles the project listed in the PROJ macro # PROJ = project # the name of the project OBJS = main.obj io.obj # list of object files# Configuration: # MODEL = s # memory model CC = bcc # name of compiler# Compiler-dependent section # %if $(CC) == bcc # if compiler is bcc CFLAGS = –m$(MODEL) # $(CFLAGS) is –ms LDSTART = c0$(MODEL) # the start-up object file LDLIBS = c$(MODEL) # the library LDFLAGS = /Lf:\bc\lib # f:\bc\lib is library directory %elif $(CC) == cl # else if compiler is cl CFLAGS = –A$(MODEL,UC) # $(CFLAGS) is –AS LDSTART = # no special start-up LDLIBS = # no special library LDFLAGS = /Lf:\c6\lib; # f:\c6\lib is library directory %else # else % abort Unsupported CC==$(CC) # compiler is not supported %endif # endif# The project to be built # $(PROJ).exe : $(OBJS) tlink $(LDSTART) $(OBJS), $(.TARGET),, $(LDLIBS) $(LDFLAGS)$(OBJS) : incl.h
