bug#49102: guix environment regression

[Mathieu Othacehe <othacehe@gnu.org>]

Hello,

When using guix@caf4a7a2, I cannot no longer build a functional
guix-daemon using the following classic commands:

--8<---------------cut here---------------start------------->8---
guix environment guix
./configure --localstatedir=/var --sysconfdir=/etc
make -j4
--8<---------------cut here---------------end--------------->8---

--8<---------------cut here---------------start------------->8---
mathieu@elbruz ~/guix [env]$ ldd ./guix-daemon 
	linux-vdso.so.1 (0x00007fff52339000)
	libz.so.1 => not found
	libsqlite3.so.0 => not found
	libgcrypt.so.20 => not found
	libbz2.so.1.0 => not found
	libstdc++.so.6 => /gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/libstdc++.so.6 (0x00007ff74ee5b000)
	libm.so.6 => /gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31/lib/libm.so.6 (0x00007ff74ed1a000)
	libgcc_s.so.1 => /gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/libgcc_s.so.1 (0x00007ff74ecff000)
	libc.so.6 => /gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31/lib/libc.so.6 (0x00007ff74eb42000)
	/gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31/lib/ld-linux-x86-64.so.2 (0x00007ff74efe8000)
mathieu@elbruz ~/guix [env]$ ./pre-inst-env guix-daemon 
guix-daemon: error while loading shared libraries: libz.so.1: cannot open shared object file: No such file or directory
--8<---------------cut here---------------end--------------->8---

When rolling back to an older guix@f1bfd9f, things work as expected. The
regression probably lies in between those 1084 commits. I'll try to
bisect more precisely later on.

Thanks,

Mathieu