$NetBSD: TODO.crosscompile,v 1.10 2023/06/27 11:20:33 riastradh Exp $

* Organize NATIVE_xyz and TARGET_xyz better.
* Organize host/target compiler tools better.
* Automatically set PACKAGES=packages.${MACHINE_ARCH}.
* Automatically set WRKDIR_BASENAME=work.${MACHINE_ARCH}.
* Simplify mk.conf setup (see HOWTO-use-crosscompile).
* Make USE_CROSS_COMPILE and MACHINE_ARCH passable on the command line.
* Make cross-OS builds work.  Use MACHINE_PLATFORM, not MACHINE_ARCH.
* Judiciously insert ${CROSS_DESTDIR} into various `.if exists(/xyz)'.
* Teach pbulk about TOOL_DEPENDS so it can easily do bulk cross-builds.
* Distinguish host build-time tools from target run-time tools.
* If you set MACHINE_ARCH, what should MACHINE be?  (Avoid using it?)
* Make sure cross-builds DTRT with INSTALL scripts.
* Handle BUILD_DEPENDS/TOOL_DEPENDS split in bsd.pkg.readme.mk.