gcc.texi bug: reference to "stupid" allocator

[David Mosberger]

Jim Wilson explained to me that gcc3 no longer includes the "stupid"
register allocator and, for that reason, the "register" keyword is now
completely ignored as far as code-generation is concerned.  AFAIK,
this breaks existing code (such as "mhz", part of lmbench), so it
might be a good idea to document this.  Also, I found that "gcc.texi"
in the 3.0 pre-release still has one reference to the "stupid"
register allocator:

	$ fgrep -i stupid gcc.texi 
	the input file name.  If stupid register allocation is in use, this

This probably should be removed.

Thanks,

	--david