what's configure

what's configure

A Configure script is an executable script designed to aid in developing a program to be run on a wide number of different computers. It matches the libraries on the user's computer, with those required by the program, just before compiling it from its source code.

what does configure do?

there are three steps must be done when a software is installed:

./configure
make
make install

1. configuring the makefile, 
2. compiling the code, 
3. and finally installing the executable in the appropriate places.

A configure script accomplishes the first of these steps. Using configure scripts is an automated method of generating  makefiles before compilation to tailor the software to the system on which the executable is to be compiled and run.

the main work configure does

use Makefile to check dependencies,library dependency checking has been done in great part using pkg-config via the m4 macro, PKG_CHECK_MODULES. Before pkg-config's gained popularity, separate m4 macros were created to locate files known to be included in the distribution of libraries depended upon.

references:

http://en.wikipedia.org/wiki/Configure_script#Dependency_checking