Hi guix,

This patch series does two things:

  * let 'glib-or-gtk-build-system' support cross-compilation

  * fix many (but not all) cross-compilation errors that prevent
    "guix build gtk+ --target=aarch64-linux-gnu" from succeeding.

It should not cause any rebuilds.  You can test with
./pre-inst-env guix build gtk+ --target=aarch64-linux-gnu.
There is still some work to be done though:

cannot build derivation `[...]-cups-filters-1.28.9.drv': 1 dependencies couldn't be built
[...] `[...]-cups-2.3.3op2.drv': 1 dependencies couldn't be built
[...] `[...]-samba-4.13.10.drv': 6 dependencies couldn't be built
[...] `[...]-libsoup-2.72.0.drv': 4 dependencies couldn't be built
[...] `[...]-rest-0.8.1.drv': 1 dependencies couldn't be built

Greetings,
Maxime