1Do not build any cross compiler in the cross-tools stage of buildworld. 2When compiling a different version of 3.Fx 4than what is installed on the system, provide an alternate 5compiler with XCC to ensure success. 6When compiling with an identical version of 7.Fx 8to the host, this option may be safely used. 9This option may also be safe when the host version of 10.Fx 11is close to the sources being built, but all bets are off if there have 12been any changes to the toolchain between the versions. 13