Merge pull request #10160 from dezgeg/pr-unset-build-hook-in-nixos-install

nixos-install: Don't use NIX_BUILD_HOOK from caller's environment

nixos/modules/installer/tools/nixos-install.sh

···
 ln -sf @shell@ $mountPoint/bin/sh
 
 
+# Build hooks likely won't function correctly in the minimal chroot; just disable them.
+unset NIX_BUILD_HOOK
+
 # Make the build below copy paths from the CD if possible.  Note that
 # /tmp/root in the chroot is the root of the CD.
 export NIX_OTHER_STORES=/tmp/root/nix:$NIX_OTHER_STORES