src2pkg recognizes many types of sources and figures out how to
configure and build them according to which files it finds in them.

autoconf	-sources which use the autotools (configure):
				autoconf, automake, aclocal and libtool
				Both Makefile and GNUmakefile are supported
configure	-sources with some other form of 'configure' script
imake		-sources which use imake/xmkmf (Imakefile)
scons		-sources using the 'scons' (SConstruct)
jam			-sources using the 'jam' (Jamfile)
python		-sources using 'python' (setup.py)
cmake		-sources using 'cmake' (CMakelists.txt)
perl		-sources using 'perl' (Makefile.PL, Build.PL, make.pl)
				each of these is handled differently
tcl			-sources using 'tcl' (install.tcl)
qmake		-sources using 'qmake' $NAME.pro
simple		-sources using 'make' (Makefile, makefile, GNUmakefile)

arbitrary commands can also be used to carry out other combinations
of commands, by setting CONFIG_COMMAND, MAKE_COMMAND and INSTALL_LINE