The configure script is generated from configure.in using autoconf, then
manually modified in two ways:

	1) the --with-x command line option is removed.
	2) the --help output for everything from --exec-prefix to
	   --target is removed, because no use is made of these.

aclocal.m4 contains an autoconf macro for locating the g++ include
directory (the include files from libstdc++). 

