sporadic build failures on freebsd

[zowoq]

These are just a couple of examples, failures seem to occur randomly and don't reoccur if the vm is restarted.

Running phase: unpackPhase
unpacking source archive /nix/store/n22iqgfwr3jr08f9hl4140y3sqmrzf2z-zlib-1.3.1.tar.gz
source root is zlib-1.3.1
setting SOURCE_DATE_EPOCH to timestamp 1705948357 of file "zlib-1.3.1/zutil.h"
Running phase: patchPhase
Running phase: configurePhase
patching script interpreter paths in ./configure
./configure: interpreter directive changed from "#!/bin/sh" to "/nix/store/35h99igbfg6aq49qxdq79gz615lscfpy-bash/bin/sh"
/nix/store/x8c40nfigps493a07sdr2pm5s9j1cdc0-patch-shebangs.sh: line 133: sed: command not found

Running phase: unpackPhase
unpacking source archive /nix/store/5cg2x1q3h8c96aszgfxiw83wvw1rz574-docbook-xsl-nons-1.79.2.tar.bz2
source root is docbook-xsl-nons-1.79.2
setting SOURCE_DATE_EPOCH to timestamp 1481323653 of file "docbook-xsl-nons-1.79.2/webhelp/docsrc/xinclude-test.xml"
Running phase: patchPhase
applying patch /nix/store/am8h4spbaylaj37952zhkqlbbcw394yy-docbook-style-xsl-non-recursive-string-subst.patch
/nix/store/vygdlg5769c8m6j48n2x8vs0fynaky73-stdenv-freebsd-boot-0/setup: line 1418: patch: command not found

[Mic92]

I strongly suspect that the gc is removing files still in use. On Linux we use procfs to counter that. On macOS it's lsof. Not sure if freebsd also use lsof. It could probably also use procfs.