Building ICI for a supported platform.

Building ICI for a supported platform is easy. Simply decide what
machine you're on and do a "make -f Makefile.$MACHINE" (where you
replace $MACHINE with the name) to create the library lib$MACHINE.a
and the interpreter ici.$MACHINE. For example under SunOS 4.1 we use
the name "sun" and Makefile.sun to build libsun.a and ici.sun. Under
NeXTSTEP we use Makefile.next etc... To see the list of supported
systems it suffices to see what configuration files exist, these files
have names in the form conf-$MACHINE.h.

The distributed makefiles build the interpreter with the default
configuration for that system. The configuration is controlled by the
system's conf-$MACHINE.h file. A configuration defines which language
extensions (collections of builtin functions) are included in the
build and overcomes some portability concerns. The file conf-sample.h
contains a prototype configuration.

Changing the configuration.

The change the configuration you edit the system's `conf' header file
and define or undefine macros to include/exclude features. The default
macros are listed below. Defining the macro REMOVES the feature from
the build (which is why the names all start with "NO"). The macros
are,

	NOMATH		Don't include mathematical builtins such as the
			trigonometric functions etc... This is useful
			on small or embedded systems that do not require
			these. On most hosted environments (i.e. those
			with a real OS) it is better to leave these in
			as you'll want them one day.

	NOWIN		Don't include the ICI text windowing functions
			(the code in win.c). ICI's text windowing provides
			a simple curses-like environment (but faster and
			smaller). There is no documentation other than the
			source however.

	NODB		Obsolete. Previous versions of ICI supported a
			text file database package which is no longer
			included. This name used to control its inclusion.

	NOTRACE		Don't include the trace() function or its support
			code. This function was an attempt to include some
			kind of debug tracing in ICI but isn't all that
			useful.

	NOWAITFOR	Don't include the waitfor() function. Useful for
			systems that don't implement BSD's select().

	NOPIPES		Don't include pipe support (popen etc.. in clib.c).
			This is used on systems such as MS-DOS that don't
			provide this.

	NOSKT		Don't include the BSD sockets functions (skt.c).
			Again useful on platforms that don't support or
			require networking.

	NOSYSCALL	Don't include Unix-style system calls (syscall.c).
			Many of these functions work on Win32 systems too.

	NODIR		Don't include the dir() function.

	NOPASSWD	Don't include the Unix password file access
			function.
