Hello,

> I suggest removing '#:tests?

Okay, done.

> Guix doesn't do staged installation

Unfortunately it seems to me that libtree fails when I remove
'(string-append "DESTDIR=" #$output)' from the make flags.

The reason is this code from libtree Makefile:

--8<---------------cut here---------------start------------->8---
install: all
	mkdir -p $(DESTDIR)$(BINDIR)
	cp -p libtree $(DESTDIR)$(BINDIR)
	mkdir -p $(DESTDIR)$(SHAREDIR)/man/man1
	cp -p doc/libtree.1 $(DESTDIR)$(SHAREDIR)/man/man1
--8<---------------cut here---------------end--------------->8---

As you can see it's using 'DESTDIR' as prefix for the installation.

- Artyom