fix for CLASSPATH/classpath switch behaviour

[Tom Tromey]

>>>>> "Nic" == Nic Ferrier <nferrier@tapsellferrier.co.uk> writes:

Nic> With Sun's tool:
Nic>   -classpath supplements the system and CLASSPATH env var
Nic>   -bootclasspath allows the system classes to be overriden, or more
Nic>    accurately it allows a new core java lib to be selected

Thanks.

Nic>   -classpath  appends extra class locations to the system and
Nic>    CLASSPATH class paths.
Nic>   -bootclasspath and -CLASSPATH overrides the CLASSPATH and builtin
Nic> Anyone any views?

Let's simply get rid of -CLASSPATH and replace it with -bootclasspath.
I think -CLASSPATH doesn't add anything above what -classpath and
-bootclasspath provide.

This will require a change to gcc/gcc.c in addition to the other
stuff.

I do think we should keep -I, since it is actually useful.
I use it in preference to the other options, since I find it easier to
remember and understand.

Tom