（1）aclocal
Aclocal m4 command generates a file, is a perl script on aclocal nature. m4 is a macro processor, which is part of the POSIX standard. Why is it called m4, stands macro, m back with four letters, is said to be the case. Excerpt description of m4: From the viewpoint of Turing m4, the input stream and output stream may join together to form an unlimited extension of the tape, m4 is the head of this tape, it is a Turing machine m4 . M4 computing power with any programming language equivalent, the difference is only reflected in the programming efficiency and operational efficiency programs written.
（2）autoconf
autoconf will configure file, configure a script that is provided to accommodate a variety of different source operating system platforms, and generates an appropriate Makefile Depending on the system, which can make your source code can be different operating systems on the platform were compiled.
（3）automake
automake will generate Makefile.in files.
FIG over a whole:
