heads up - gcc toplevel bootstrap activated

[Paolo Bonzini]

This is just a heads up that GCC has switched so that the toplevel 
coordinates the bootstrapping.

The main change is that on a native configuration `make' will 
automatically bootstrap, unless you configure with --disable-bootstrap 
(and, since the binutils list is receiving this message, if you 
bootstrap a combined tree, the assembler and linker will also be built 
three times, each time using the previous one).  There should be no 
behavior change for cross configurations, nor for trees not including GCC.

Let me know if I broke something.

Paolo