From ed66d010659a710646f5f1015c97a58614a713b3 Mon Sep 17 00:00:00 2001
From: Mateusz Piotrowski <0mp@FreeBSD.org>
Date: Mon, 28 Sep 2020 15:23:21 +0200
Subject: [PATCH] Fix tar invocation on FreeBSD

tar(1) on FreeBSD does not use standard output or input when the -f flag
is not provided. Instead, it defaults to /dev/sa0 on FreeBSD.

Make this tar invocation a bit more robust and explicitly tell tar(1) to
use standard output.

This is one of the issues discovered while porting Nix to FreeBSD. It has
been tested and committed locally to FreeBSD ports:
https://svnweb.freebsd.org/ports/head/sysutils/nix/Makefile?revision=550026&view=markup#l108
---
 tests/tarball.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/tarball.sh b/tests/tarball.sh
index 88a1a07a0..fe65a22e4 100644
--- a/tests/tarball.sh
+++ b/tests/tarball.sh
@@ -17,7 +17,7 @@ test_tarball() {
     local compressor="$2"
 
     tarball=$TEST_ROOT/tarball.tar$ext
-    (cd $TEST_ROOT && tar c tarball) | $compressor > $tarball
+    (cd $TEST_ROOT && tar cf - tarball) | $compressor > $tarball
 
     nix-env -f file://$tarball -qa --out-path | grep -q dependencies