Re: probs cross-building current libstdc++-v3, because of need to link?

[Phil Edwards <phil at jaj dot com>]

My hands wrote the following before consulting my brain:

> ...yah, methinks I know what I've forgotten.  Patch in progress.

Belay that.  Patch not in progress.  Sleep in progress.

There is a semi-nifty macro in modern autoconf called AC_NO_EXECUTABLES,
which turns off the tests involving a linker.  But it can't be called
unconditionally, because in a native build we want to do those link tests.
Nor can it be called conditionally, like

    if (it's a cross build) then
        AC_NO_EXECUTABLES
    fi

because it's not just shell code; it has other effects at 'autoconf' time.

In fact, trying to use it at all causes fatal autoconf errors.  (One of
the "other effects" is to flag an error if you try to do a linking test.
Which we do.  They're not on the same code path, but autoconf can't
know that.)

We may have to do something devious here, such as redefining the same
things that AC_NO_EXECUTABLES does, but without the killer side effects,
but right nBrain panic: falling asleep in 10 secoNO CARRIER