Exactly when does autoconf enter cross-compilation mode?

[wferi]

Hi,

https://www.gnu.org/software/autoconf/manual/autoconf-2.69/html_node/Hosts-and-Cross_002dCompilation.html
is rather hard to follow in general, but also contains the following
clear-cut statement: "Now, configure enters cross-compilation mode if
and only if --host is passed."

However, if I pass in my build architecture Autoconf 2.69 reports:

$ ./configure --host=x86_64-linux-gnu
checking for x86_64-linux-gnu-gcc... x86_64-linux-gnu-gcc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.out
checking for suffix of executables... 
checking whether we are cross compiling... no
[...]

That is, it finds the compiler with the prefixed name but does not enter
cross-compilation mode.  Does "cross-compilation mode" mean something
different, do I misunderstand the documentation, or what is the
resolution of this apparent (to me) contradiction?

(Please Cc me, I'm not subscribed.)
-- 
Thanks,
Feri