[Darwin, configury] No longer expect to find cross-target headers on the host.

[Darwin, configury] No longer expect to find cross-target headers on the host.

Earlier Darwin (esp. Darwin8 and Darwin9) had FAT libraries and suitable header
installations in /usr/include such that one could build a cross-toolchain
(including cross-arch) using a common sysroot (including / for “current” version).

However this is no longer true on a number of levels.  A vanilla Darwin system has
no headers installed in /usr and it's certainly not appropriate to try and find
headers/libs for (say) x86-64-darwinNN X powerpc-darwin in /usr on any Darwin NN > 10
(even Darwin10 is incomplete in that it omits the ppc64 multilib).  In the latter
example, the catch-all in the current configury to mean that
"foo-darwin" == “foo-version-on-this-system” breaks the cross case
—target=powerpc-apple-darwin —host=some-system-later-than-darwin10.

gcc/

2016-12-11  Iain Sandoe  <iain@codesourcery.com>

	* configure.ac (CROSS directory tests): Remove the assumption that
	Darwin hosts contain suitable target sysroots in "/".
	* configure: Regenerate.

From-SVN: r243533