casts and constants

[utzoo!duke!unc!smb]

The Ritchie C compiler does not treat the construct

	(char) 100

as a constant.  This means that statements like

	switch(c) {
		case (char) 0x80:	foobar();

are illegal.  The Portable C compiler on the 11, and the VAX C compiler
do not suffer from this problem.