[source] include/prereq-build.mk: Add xz-utils to make prereq

[LEDE Commits]

jow pushed a commit to source.git, branch master:
https://git.lede-project.org/ed768ae4b2f744883765cae4d7e5f7f62249de01

commit ed768ae4b2f744883765cae4d7e5f7f62249de01
Author: Daniel Engberg <daniel.engberg.lists at pyret.net>
AuthorDate: Tue Oct 4 06:34:43 2016 -0500

    include/prereq-build.mk: Add xz-utils to make prereq
    
    Add xz-utils to make prereq
    
    Signed-off-by: Daniel Engberg <daniel.engberg.lists at pyret.net>
---
 include/prereq-build.mk | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/prereq-build.mk b/include/prereq-build.mk
index 4a0509a..b2f5699 100644
--- a/include/prereq-build.mk
+++ b/include/prereq-build.mk
@@ -164,6 +164,9 @@ $(eval $(call SetupHostCommand,git,Please install Git (git-core) >= 1.7.12.2, \
 $(eval $(call SetupHostCommand,file,Please install the 'file' package, \
 	file --version 2>&1 | grep file))
 
+$(eval $(call SetupHostCommand,xz,Please install xz-utils, \
+	xz --version | grep XZ))
+
 ifneq ($(HOST_OS),Darwin)
 $(eval $(call SetupHostCommand,openssl,Please install the 'openssl' utility, \
 	openssl version | grep '\(OpenSSL\|LibreSSL\)'))